The authors studied white polymer light emitting diodes (PLEDs) based on blue exciton emission by poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and orange-to red emission from exciplexes formed at the interface between the PFD and poly(4-methyl-triphenylamine-co-acetoaldehyde) (TPA-AA). It is thought that the orange-to-red light-emitting exciplexes formed at the TPA-AA/PFD interface have intermolecular charge-transfer (CT) characteristics, namely, TPA-Ag+.PFD-, in which TPA-AA and PFD act as a donor (D) and an acceptor (A), respectively, and long intermolecular distances. TPA-AA is a nonconjugated polymer with good solubility in chloroform and acts as a hole transport layer (HTL). A bilayer PLED, ITO (indium tin oxide)/TPA-AA/PFD/Al, was fabricated by spin-coating, and white electroluminescence (EL), corresponding to Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.36, 0.28) and a brightness of 39.6 cd/m(2), was achieved at 16 V. In order to decrease the turn-on voltage and enhance brightness, a pi-conjugated polyelectrolyte, poly(9,9-bis[6'-(N,N,N,-trimethylammonium)hexyl]fluorine-co-alt-1,4-phenylene) bromide (PFN+Br-), was used as an electron injection layer (EIL). This trilayer PLED, ITO/TPA-AA/PFD/PFN+Br-/Al, showed white EL corresponding to CIE chromaticity coordinates of (0.25, 0.31) and a brightness of 1450 cd/m(2) at 14 V. In the bilayer PLEDs, orange-to-red exciplex emission at similar to 630 nm was dominant at a low applied voltage, while at high voltage, blue exciton emission at similar to 430 nm and excimer emission at similar to 490 nm were comparable in strength to the exciplex emission. Meanwhile, the trilayer PLEDs showed mainly blue exciton emission at low voltage, and orange-to-red exciplex emission that was comparable in strength to the exciton emission at high voltage. These results can be explained by the different degrees of hole accumulation at the TPA-AA/PFD interface, which affects the electric field distribution in the PFD layer and the EL emission processes. Based on the applied voltage dependence of the emission colors of the bilayer and trilayer PLEDs, two types of models, namely, PLED band diagrams and Marcus-type molecular diagrams that represent hole transfer from TPA-AA to PFD, were proposed to explain the working principles of the devices. The working principles presented in this manuscript are different from the recently proposed working principle based on the Auger mechanism for small-molecule organic light-emitting diodes (OLEDs) based on D/A heterojunctions (He et al., Adv. Mater. 2016, 28, 649-654). Having a detailed understanding of the working principles is critical for designing efficient OLEDs, and our models give a new insight into the working principles of OLEDs based on D/A heterojunctions. Furthermore, these models provide a useful means of realizing efficient white PLEDs based on blue exciton emission and orange-to-red exciplex emission.

Two bis(acetylide)-functionalized platinum(II) polymers containing ferrocenyl pendant ligands, trans[(-Pt(PBu3n)(2)-C CRC C-)(n) P1 (R = 9-ferrocenylmethylene-2,7-diethynylfluorene) and P2 (R = ferrocenylmethylene-2,5-diethynylbenzene), were prepared in good yields and were characterized by NMR spectroscopy and GPC. Electrochemical characteristics with copolymers P1 and P2 as the cathode active materials for rechargeable lithium batteries showed chemical and electrochemical reversibility. The thin layer polymer electrodes of P1 and P2 exhibited reversible redox peaks at the potentials of 0.54 and 0.64 V (vs. Ag/AgCl), respectively. The P1 or P2/carbon composites are also used as cathode-active materials to enhance the conductivity and durability. The electrodes exhibited good cycle life of over 50 charging/discharging cycles and no reversible n-type redox abilities seemed to be available. (C) 2015 Elsevier B.V. All rights reserved.

Totally reversible redox-active polymers, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl functionalized polyacrylic acid (PTAm-A) and poly(tripyridiniomesitylene) (PTPM), both of which possessed rapid charge transport properties in an aqueous electrolyte, were applied to a polymer-sandwiched device to offer an electrochemical current rectification functionality. Single-layer and bilayer devices were fabricated employing the PTAm-A and/or PTPM thin layer(s) as charge transport media. Single-layer devices with a 1 cm(2) electrode area demonstrated large currents in the order of several milliamperes, which were established by redox mediation based on a fast electron self-exchange reaction between adjacent redox sites in the polymer layers. A current-voltage response obtained from the bilayer device exhibited a rectification effect due to thermodynamically favoured cross reaction at the polymer/polymer interface, retaining the large current densities. The observed currents were comparable to those predicted from the diffusion-controlled charge transport kinetics. Potentiostatic measurements revealed that the rectified current readily achieved a steady state in response to the applied voltage. These results demonstrate that the PTAm-A/PTPM thin-layer heterojunction enabled a large current rectification based on the redox mediation process, providing insight into ideal charge flow systems in various electrochemical devices.

Two pendant-type naphthalene diimide (NDI) polymers bearing a polynorbornene backbone were prepared and their electrochemical properties explored. The NDI-based polymers displayed reversible redox responses in 1 M LiClO4 gamma-butyrolactone electrolyte. Polymer 1, bearing a N-methyl group, exhibited remarkable charge-storage capabilities which demonstrated its potential usefulness as an organic cathode-active material in rechargeable devices with excellent performances such as large charge capacity, high rate capability, and charge-discharge cyclability.

Oxygen-oxidative polymerization of diphenyl disulfide gives poly(1,4-phenylene sulfide) (PPS), catalyzed by a vanadyl complex and a protic acid. N,N'-Ethylenebis(salicylideneaminato)oxovanadium(IV) (VO(salen)) which has been reported to be catalytically inactive at ambient temperature because of the insufficient reactivity of its oxidized state, an oxovanadium(V) complex, for the oxidation of the monomer turned out to exhibit an excellent catalytic activity on raising the reaction temperature above 100 degrees C. The enhanced reactivity of VO(salen)-acid or bis(2,4-pentanedionato)oxovanadium(IV) (VO(acac)(2))-acid catalytic systems at elevated temperatures gave insight into the catalytic mechanism where oxidation of the monomer with the oxovanadium(V) complex dominated the reactivity, which was also accelerated by a second redox shuttle molecule, such as quinones with a potential near that of the [VO(salen)](0/+) couple.

The synthesis, characterization and biological study of a new 3,4,5-trisubstituted isoxazolones have been reported, whereby a series of (Z)-3-methyl-4-(2-(R-phenyl) hydrazinylidene) isoxazol-5(4H)-ones were prepared by the reaction of a beta-diketohydrazone with hydroxylammonium chloride. All the products were characterized using EA, UV-Vis, FT-IR, H-1-NMR, C-13-NMR spectroscopy and HMBC. The crystalline and molecular structures of three compounds were solved by X-ray diffraction methods. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed to obtain a better explanation of the observed experimental behaviour of these newly synthetized compounds. Furthermore, the reports of cytotoxicity and an antiproliferative effect in human promyelocytic leukaemia cells, HL-60, was tested by the MTT reduction method, showing that most of the newly synthetized compounds had important antineoplastic activity. The most active isoxazolones were used in reverse transcription polymerase chain reaction (RT-PCR) experiments to determine the effect on the expression levels on mRNA encoding using the anti-apoptotic, Bcl 2, pro-apoptotic, Bax, and the proliferation inhibition, p21(WAF-1), proteins. Therefore, it was possible to fully characterize the complete library of 15 isoxazolones and to show that most of them are antineoplastic trough an apoptotic pathway.

The ionic conductivity of a liquid crystal electrolyte was switched along with redox reactions of polyviologen. The surface charge of the polymer determined the alignment and the bulk conductivity of the electrolyte. The cooperative switching firstly enabled the suppression of self-discharging and quick-response, giving rise to facile and persistent charge storage.

Reversible addition-fragmentation chain transfer polymerization yields reactive block copolymers bearing the pentafluorophenyl ester (PFPA) group, and subsequent Click amidation using 2,2,6,6-tetramethylpiperidine-N-oxyl- and imidazolium-functionalized primary amines produces the corresponding functional block copolymers, leading to installation of statistical radical-and ionic sites into the PFPA segment. The monolayered thin film devices fabricated using the obtained block copolymers exhibit repeatable switching of electric conductivity (on/off ratio > 10(3)) under a bias voltage, which reveals that the coexistence of radicals and ions in the same spherical domain of the copolymer layer is a prerequisite for repeatable switching memory.

Association of n-hexanol molecules in cyclohexane forming clusters is studied by DFT and H-1 NMR. Geometry optimization, corrected binding energies, charge distributions, charge transfer energies, and 1H NMR chemical shifts have been obtained. The calculated chemical shifts of hydroxyl protons have been correlated to experimental data obtained in the range of n-hexanol molar fraction between 0.002 and 0.2, showing that n-hexanol molecules at a molar fraction around 0.1, where well-structured hydrogen bond networks are observed, tend to form linear pentamers and hexamers. The experimental data are consistent with the continuous linear association thermodynamic model, showing a dimensionless association constant of 284. (C) 2015 Elsevier B.V. All rights reserved.

The formation of emulsions upon reverse self-association of the monodisperse amphiphilic block copolymer poly(ethylene oxide)(43)-b-poly(epsilon-caprolactone)(14) in cydohexanone is reported. Such emulsions are not formed in toluene, chloroform, or dichloromethane. We demonstrate by magnetic resonance spectroscopy the active role of the solvent on the stabilization of the emulsions. Cyclohexanone shows high affinity for both blocks, as predicted by the Hansen solubility parameters, so that the copolymer chains are fully dissolved as monomeric chains. In addition, the solvent is able to produce hydrogen bonding with water molecules. Water undergoes molecular exchange between water molecules associated with the polymer and water molecules associated with the solvent, dynamics of major importance for the stabilization of the emulsions. Association of polymeric chains forming reverse aggregates is induced by water over a concentration threshold of 5 wt %. Reverse copolymer aggregates show submicron average hydrodynamic diameters, as seen by dynamic light scattering, depending on the polymer and water concentration.

The authors report on white polymer light-emitting electrochemical cells (PLECs) fabricated with a polymer blend film composed of a blue fluorescent pi-conjugated polymer (blue FCP), poly(9,9-di-n-dodecylfluoreny1-2,7-diyl) (PFD), and a red-orange FCP, poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), based on concepts of band-structure engineering. Polymer blending is one of the simplest and most promising methods for fabrication of van der Waals interfaces, which convert electricity to light in PLECs. By optimizing the composition of PFD, MEH-PPV, poly(ethylene oxide) (PEO), and salt (KCF3SO3) in the active layer, white-light emission with Commission Internationale de l'Edairage (CIE) coordinates of (x = 0.33, y = 0.31) can be achieved through light mixing of blue exciton emission from PFD and red-orange exciton emission from MEH-PPV at an applied voltage higher than the threshold voltage,141,"-FcP, which corresponds to E-g(blue)-(FCP)/e, where E-g(blue-FCP) is the band gap of PFD and e is the elemental charge. The white light produced by light mixing of PFD and MEH-PPV emissions can be obtained at a low MEH-PPV concentration, while only red-orange emissions from MEH-PPV are obtained at high MEH-PPV concentrations. The emission color of FCP-blend PLECs can be explained by Forster resonance energy transfer (FRET) from the excited PFD to the MEH-PPV because the photoluminescence (PL) spectrum of PFD overlaps with the UV vis absorption spectrum of MEH-PPV. However, FRET was limited by the presence of PEO in the active layers of the FCP-blend PLECs. This meant it was much easier to tune the emission colors compared to FCP-blend polymer light-emitting diodes (PLEDs), in which FRET occurs predominantly. Utilization of a polymer blend film of blue and red-orange FCPs in PLECs is a very effective and promising method for fabrication of white light-emitting devices.

Photochromic solid materials based on the cationic polymer poly(decylviologen) are reported. The solids were obtained by freeze-drying colloidal suspensions of nanocomplexes obtained by mixing aqueous solutions of the polycation with different solutions of polyanions such as poly(sodium 4-styrenesulfonate) or sodium alginate, at a cationic/anionic polymeric charge ratio of 0.7. The photochromic responses of the solid materials fabricated with alginate as complementary charged polyelectrolyte of the cationic polyviologen are faster than those of the solid materials fabricated with poly(sodium 4-styrenesulfonate), achieving coloration kinetics in the order of minutes, and discoloration kinetics in the order of hours for the former. Aromatic-aromatic interactions between the latter polyanion and the polyviologen may stabilize the dicationic form of the viologen derivative, increasing the necessary energy to undergo photoreduction, thus decreasing the reduction kinetics.

Visualization of the oxygen partial pressure (p(O(2))) was performed at the surface of a gas diffusion layer (GDL) and the upper part of the gas-flow channel of the cathode of an operating polymer electrolyte fuel cell (PEFC) with straight flow channels by using an oxygen-sensitive luminescent dye film. The gradient of p(O(2)) inside a channel was clearly observed, even on the GDL surface across the channel. A numerical simulation was performed to understand the reaction distributions inside the PEFC. By visualization and numerical simulation, the distributions of p(O(2)), the current density, water concentration, and temperature in the operating PEFC were obtained, and the relationships between the parameters were studied. Supersaturated water inside the cell was found both experimentally and computationally. p(O(2)) and the water concentration were concluded to be the two most important factors in determining the distribution of power generation.

The integration of functional components such as metal nanoparticles, metal salts, or ionic liquids with well-defined block copolymer (BCP) nanotemplates via non-covalent bond interactions has afforded hybrid functional materials. Here, we designed an ionic liquid (IL)-functionalized redox-active TEMPO (2,2,6,6-tetramethylpiperidine-N-oxy) radical (guest), investigated phase-selective incorporation/placement into host BCP nanostructured matrices, and established a rational approach to functionalize BCP templates. On-demand domain functionalization of poly(styrene-b-ethyl-ene oxide) (PS-b-PEO) was triggered by ion-ionophore interaction, as verified by the suppression of PEO melting transition in DSC, and the swelling behavior of the PEO spherical domain in AFM, TEM, and X-ray scattering characterizations. The obtained BCP layer containing the redox-active TEMPO and IL was utilized as an active layer in the diode-structured memory device, which exhibited on/off resistive switching (on/off ratio >10(3)). Systematic placement of TEMPO and IL in the BCP spherical domain allowed for tuning of the switching characteristics and revealed that the formation of a discontinuous redox-active domain was critical for rewritable resistive switching.

A newly established catalyst system for oxygen-oxidative polymerization of diphenyl disulfide is reported. Combination of vanadyl compounds (e.g., VO(acac)(2)) and triphenylmethylium tetrakis(pentafluorophenyl) borate (TrB(C6F5)(4)) proceeds the polymerization to give poly(1,4-phenylene sulfide) (PPS) at 100 degrees C. When triphenylmethylium tetrafluoroborate (TrBF4) is applied with vanadyl tetraphenylporphyrin (VO(TPP)) or N,N'-(ethylenebis(salicylideneaminato)) oxovanadium (VO(salen)), PPS is also given via polymerization under conditions near 160 degrees C. Combination of the vanadyl complex and the borate affords the first protic-acid-free catalytic system for the polymerization of the disulfide, suggesting the overall reaction to produce PPS and H2O from O-2 and protons that are eliminated from the monomer.

Oxidative polymerization of diphenyl disulfide under molten conditions at moderately elevated temperatures gave poly(1,4-phenylene sulfide) (PPS), using a vanadyl complex strong acid catalyst with oxygen as the ultimate oxidant. Origin of the selectivity of the sulfonium electrophile for the formation of the 1,4-thiophenylene chain, characterized by the presence of a disulfide bond at the chain end, was determined by the behavior of polymerization and structural analysis of the product together with a computational calculation, which revealed a unique chain growth-type polycondensation process.

Block copolymers of 2,2,6,6-tetramethyl-4-piperidyl methaaylate and glycidyl methactylate were prepared by atom transfer radical polymerization. The block copolymer was immobilized on an indium-doped tin oxide substrate by simply coating the copolymer solution and annealing. The copolymer layers were efficiently converted to those of the corresponding 2,2,6,6-tetramethylpiperidin-1-oxy (TEMPO) polymer. The TEMPO layers were swelled with but not eluted into common electrolyte solutions such as acetonitrile and ethylene carbonate, and showed excellent electrochemically reversible redox cycling at 0.81 V vs. Ag/AgCl. The layer with the thickness of micron meters exhibited both a sufficient charge diffusivity (10(-10) cm(2) s(-1)) and a very large storage capacity (beyond 120 mC cm(-2)), which was applicable to a cathode of organic-based rechargeable devices. (C) 2015 Elsevier Ltd. All rights reserved.

A dye-sensitized solar cell (DSSC) was fabricated with a viologen polymer as a charge-storable electrode and an aqueous electrolyte. The polyviologen was prepared via electrolytic polymerization of the 4-cyanopyridine moiety: It displayed reversible two-electron redox reactions at -0.48 and -0.86 V vs. Ag/AgCl in the aqueous electrolyte, which were appropriate for the acceptance of an electron from the photo-anode or TiO2 conduction band by the charge-storable electrode. The DSSC using the polyviologen electrode achieved both photo-current generation with a high open-circuit voltage of ca. 0.8 V upon light irradiation, and a charge-supply after irradiation at a constant voltage of ca. 0.4 V with a discharging capacity of ca. 75% of the polyviologen electrode. The potential tuning of the organic-based polyviologen electrode was described. (C) 2015 Elsevier Ltd. All rights reserved.

A nitroxide radical-substituted polyether, poly(TEMPO-substituted glycidyl ether) (PTGE), was synthesized using a potassium tert-butoxide/18-crown-6 initiator. The presence of 18-crown-6 effected significant improvement in the reactivity of the chain end, thus allowing the polymerization to proceed at moderate temperatures to suppress the deactivation of the pendant nitroxide group. A high molecular-weight polyether with a theoretical radical concentration was first obtained in high yield. Charging and discharging cyclability was much improved by cross-linking, which helped the electrode-active material stay on a current collector during the electrolysis. The polymer/vapor-grown carbon nanofiber composite electrode exhibited a redox capacity comparable to the formula weight-based theoretical density over 10(3) cycles and fast charging/discharging capability up to a rate of 60C which corresponded to full charging and discharging in 60s. The redox capacity was almost maintained for a composite layer with a remarkably high polymer ratio of 90%, which demonstrated the presence of effective percolation network of the carbon nanofiber due likely to the affinity of the polyether to the carbon material.

An excellent functional group tolerance of ruthenium complex catalysts for olefin metathesis gave rise to ring-opening polymerization of norbornene functionalized with redox-active anthraquinone (AQ) pendants, yielding a high-molecular-weight and processable polynorbornene with large redox capacity. A thin layer of the polymer cast on current collectors showed reversible redox reaction at -0.85 V vs Ag/AgCl when immersed in basic aqueous electrolyte solutions. Good cycle performance was observed with a capacity comparable to the formula weight-based theoretical density of 212 mAh/g, which was the largest among those for the previously reported redox-active polynorbornenes. This suggested that all of the AQ units in the layer were redox-active, that electroneutralization was accomplished by successive compensation of counterions throughout the layer, and that the mechanical strength of the polymer layer prevented dissolution or exfoliation from the current collector surface. A robust polymer-air secondary battery with the high capacity was fabricated by using the polymer layer as the anode-active material. The battery showed a discharge voltage of 0.68 V and long life of over 300 cycles of charging/discharging, maintaining the moderate energy density of 143 mWh/g.

Concurrent and cathodic electrolysis of tris(cyanopyridinio)mesitylene and zinc chloride gave redox-active polyviologen, densely formed around the zinc oxide nanorod, on a substrate, which displayed a large charging discharging capacity and an excellent rate performance based on a large diffusivity of charge, and was useful as an anode-active material.

Concurrent and cathodic electrolysis of tris(cyanopyridinio)mesitylene and zinc chloride gave redox-active polyviologen, densely formed around the zinc oxide nanorod, on a substrate, which displayed a large charging discharging capacity and an excellent rate performance based on a large diffusivity of charge, and was useful as an anode-active material.

A copolymer of TEMPO-and aniline-substituted norbornene was prepared by ring-opening metathesis polymerization of the corresponding monomers. Electropolymerization of the pendant aniline groups in the copolymer gave a layer of polynorbornene populated with the redox-active TEMPO pendants, in which polyaniline chain was incorporated. Electroactivity of the TEMPO pendants throughout the layer and its excellent charging/discharging cyclability, in addition to the amorphous nature of the layer, suggested that the polyaniline chain was homogeneously dispersed in the layer and that each chain served as crosslinking moiety. The effect of the polyaniline chains was further enhanced when they were formed by in-situ electropolymerization of the aniline group in the preformed layer of the copolymer/polyaniline composite. The polyaniline chain served as a conducting path to reduce the charge-transfer resistance for redox mediation, which gave rise to an excellent rate performance for the charging/discharging process of the layer, compared with those for the composite layers of TEMPO-substituted polymers with polyaniline and other conductive additives prepared by the conventional grinding methods.

Electrolytes highly enriched with oxygen for lithium-oxygen (Li-O-2) batteries were prepared by combining perfluorohexyl bromide as an oxygen-uptake perfluorochemical (PFC) medium with lithium perfluorooctane sulfonate (LiPFOS) as a perfluoro-surfactant and a supporting electrolyte, which allowed an exceptionally high miscibility of PFCs with tetraethylene glycol dimethyl ether (TEGDME). The electrochemical reduction current of oxygen was enhanced three times in the LiPFOS-TEGDME electrolyte with ca. 60 wt% PFC content in comparison with that of a conventional Li-O-2 battery electrolyte, which was ascribed to the high oxygen solubility of the electrolyte. A Li-O-2 cell fabricated with the PFC-based electrolyte exhibited an excellent discharging capacity of 6500 mA h g(-1) which was approximately 1.5 times higher than that obtained with the conventional electrolyte.

Redox-active, phenothiazine-functionalized polymers were synthesized and employed as a promising cathode-active material (similar to 3.7 V vs. Li, 77 Ah kg(-1)) in a rechargeable battery. The longer spacer between phenothiazine and the polymer backbone contributed to the stability of the formed radical cations, resulting in decelerated self-discharge and improved cycle performance.

Visualization inside polymer electrolyte fuel cells (PEFCs) for elucidating the reaction distributions is expected to improve the performance, durability, and stability. An oxygen-sensitive film of a luminescent porphyrin was used to visualize the oxygen partial pressures in five straight gas-flow channels of a running PEFC with liquid-water blockages formed at the end of the channels. The blockage greatly lowered and unstabilized the cell voltage. The oxygen partial pressure decreased nearly to 0 kPa in the blocked channel. With a water blockage in a channel, the oxygen partial pressures in the adjacent channels were lowered due to an extra demand of oxygen consumption. When the number of the blocked channels increased, the oxygen partial pressure in the unblocked channels became much lowered. When the water blockages disappeared, the oxygen partial pressures quickly returned to the values before plugging. The influence of the cross flows of air through the gas diffusion layers in straight channels was much smaller than that in serpentine flow channels. (C) 2014 Elsevier B.V. All rights reserved.

With the aim of achieving supramolecular structures containing dyes with controlled state of aggregation, the formation of ternary complexes between 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin, poly(decylviologen), and sulfobutylether-beta-cyclodextrin at low excess of the cyclodextrin is described. By controlling the stoichiometry of the reactants, both non-fluorescent H-aggregates of the dye and stabilized fluorescent monomers may be obtained. The dye undergoes self-aggregation in the presence of the flexible, cationic polymer, and by addition of the negatively charged cyclodextrin the aggregates are cleaved. The cyclodextrin primarily induces the inclusion of 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin in its cavity, and the ensemble is stabilized by the polymer by means of electrostatic, hydrophobic, and/or aromatic aromatic interactions. The ternary complex thus produced tends to nano-fiber formation, as seen by FE-TEM. (C) 2014 Elsevier Ltd. All rights reserved.

Reactivity of redox-active molecules for heterogeneous electron-transfer processes at the surface of doped zinc oxide substrates depended on their energy levels. The redox-active molecules with negative redox potentials displayed a reversible electrochemical response but those with positive redox potentials were characterized by slow electrode kinetics, which was attributed to more than three times larger heterogeneous electron-transfer rate constant for the former redox-active molecules. A photovoltaic cell using methyl viologen as an acceptor molecule, TEMPOL as a donor molecule, and the doped ZnO as the transparent conducting substrate gave high photovoltage, which was ascribed to the reactivity of the redox-active molecules at the doped ZnO surface.

A crosslinked poly(4-glycidyloxy TEMPO) was synthesized via anionic ring-opening copolymerization of 4-glycidyloxy TEMPO and a diglycidyl ether using a pentaerythritol/phosphazene base initiator. A fast and reversible charge storage capability was established for the polyether/SWCNT composite layer with a large layer thickness of several tens of micrometres, despite the low SWCNT content of 10% which was much closer to the percolation limit than the amount required for the previously reported TEMPO-substituted polymethacrylate.

Visualization of the oxygen partial pressures was carried out at the surface of a gas diffusion layer (GDL) for the first time together with the upper part of the gas-flow channel of the cathode of a running polymer electrolyte fuel cell (PEFC) using two different oxygen-sensitive luminescent dye films. The visualized distributions of the oxygen partial pressures at the GDL and the upper gas-flow channel during the PEFC operation were very different in a conventional test cell. The change in the distribution of the oxygen partial pressures was observed by changing the oxygen utilization, which should be connected with the reactive locations in the membrane-electrode assembly (MEA). A numerical calculation was carried out to understand the distributions of water and current density inside the MEA. The water distribution inside the MEA was confirmed to strongly affect the distributions of the current density and the oxygen /partial pressure. (C) 2014 Elsevier B.V. All rights reserved.

Poly(norbornene)-g-poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl) (PNB-g-PTMA) was prepared by a grafting-through approach based on anionic polymerization of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl using a norbornene-substituted diphenylhexyllithium to yield a norbornene-functionalized macromonomer (NB-PTMA) and subsequent ring-opening metathesis polymerization of NB-PTMA using a Grubbs third-generation catalyst, which avoided critical side reactions involving the nitroxide radical of TEMPO moiety. The anionic polymerization resulted in high yields (>94%), narrow polydispersity indices (<1.20), and radical concentrations (0.95 radicals per monomer unit). The ROMP also resulted in high yields (>98%) and high radical concentrations (0.95 radicals per monomer unit), by virtue of the functional group tolerance of these reactions. Single molecular dimension of PNB-g-PTMA was measured by dynamic light scattering and by atomic force microscopy (AFM), which precisely reflected the bottlebrush structure to reveal the presence of the TEMPO group crowded at the periphery of the molecule. The lengths of PNB-g-PTMA along the macromolecular side chains and the polynorbornene main chain were both approximately equal to the theoretical lengths estimated by the degree of polymerization for each chain. The number-average diameter of PNB-g-PTMA in THF increased with initial NB-PTMA ratio to the Grubbs catalyst. Photo-cross-linked thin layer electrodes of PNB-g-PTMA demonstrated the reversible redox reaction at 0.80 V vs Ag/AgCl corresponding to the TEMPO/TEMPO+ couple and quantitative charging/discharging processes even at 120 C rate (i.e., full charging in 30 s). As a novel application of redox-active polymers, PNB-g-PTMA exhibited 95% efficiency of the theoretical charge capacity in a flow cell system, based on the unique properties of bottlebrush polymers such as the defined molecular dimension and relatively low solution viscosity in comparison with corresponding linear polymers.

In this work we present a study on the association of n-hexanol in cyclohexane using NMR and NIR spectroscopies. Abrupt changes on spectroscopic responses have been observed at low molar fractions of n-hexanol, which are related to hydrogen bond network formation that includes trace water. Molecular interactions are found to be dominated by dispersion forces, hydrogen bonding, and dipolar interactions, to different extents at different n-hexanol composition ranges. 1D, DOSY, and T-1 and T-2 relaxation time analyses by H-1-NMR allow understanding the dynamics of the mixtures. NIR allows verifying the formation of n-hexanol polymeric species. In addition, an n-hexanol/cyclohexane mixture with an alcohol molar fraction of 0.177 has been titrated with water, revealing the formation of a microemulsion containing water droplets that evolves to a bicontinuous microemulsion with increasing water content. Stable boundary water is detected at the microemulsion interface. (C) 2014 Elsevier B.V. All rights reserved.

The immobilization of the hydrophilic low molecular-weight cationic molecules rhodamine 6G, methylene blue, and citidine in nanoparticles composed of two opposite charged polyelectrolytes, poly(sodium 4-styrenesulfonate) and chitosan, is studied, and the results correlated with their physicochemical properties. Nanoparticles containing both polyelectrolytes have been synthesized showing hydrodynamic diameters of around 200 nm and tunable zeta potential. It was found that the strength of binding of the cationic molecules to the polyanion bearing charged aromatic groups poly(sodium 4-styrenesulfonate) by means of short-range aromatic aromatic interactions increases with their hydrophobicity and polarizability, as seen by H-1 NMR and UV vis spectroscopies, and diafiltration. Consequently, association efficiencies of 45, 21, and 12% have been found for the three molecules, respectively, revealing the different ability of the molecules to be immobilized in the nanoparticles. These results provide a proof of concept on a new strategy of immobilization of hydrophilic low molecular-weight molecules based on aromatic aromatic interactions between polyelectrolytes and their aromatic counterions.

Ring-opening metathesis polymerization (ROMP) using Grubbs third-generation catalyst directly yielded a norbornene-based polymer bearing robust redox-active radicals without any protection. Successive addition of imidazolium-containing norbomene in a one-pot reaction during ROMP produced pendant radical- and ion-containing block copolymers. The diode-structured thin-film devices fabricated with the obtained block polymers that had morphologies of spheres, lamellae, and inverse spheres exhibited conductive switching (write-once read-many-times, WORM) under a bias voltage, which revealed the dominant effect of the location of radicals and ions in the microphase-segregated domains on memory characteristics.

Tris(2-aminoethyl)amine-based urea and thiourea derivatives interacted with a superoxide anion (O-2(-)) and peroxide dianion (O-2(2-)): The redox potential of oxygen was positively shifted with the molecules through their multiple-hydrogen-bond donor ability.

Network polymers of cobaltporphyrin derivatives are prepared by a facile click reaction via the Michael addition of acetoacetate-substituted tetraphenyl cobaltporphyrin and tri- or tetra-acrylates. The conversion is saturated for 1 h in the presence of a catalyst, which almost reaches the same gelation point of the formed network polymers. Deeply and homogeneously red-colored membranes with a sub-micrometer thickness are yielded on a porous supporting membrane. They are still tough even with a very high content of the rigid porphyrin residue. The oxygen permeability is high, at 10-100 Barrer, and the oxygen/nitrogen permselectivity (P-O2/P-N2) is significantly enhanced with the porphyrin content reaching 30, for the membranes with ca. 70 wt% porphyrin content.

Silicon wafers both without and with silicon(IV) oxide surface coverage were covered with benzene solutions of stable organic radical 3-(N-tert-butyl-N-aminoxyl)benzoic acid (mNBA). X-ray photoelectron spectroscopy supported the presence of the radical on both surface-cleaned (oxide-reduced) and oxide-covered surfaces. Optical waveguide spectroscopy showed that the radical retained its structure while adsorbed to the surface of the wafers, without noticeable decomposition. AFM and MFM imaging showed that the radical formed blocky particles with a change in rms roughness from 0.3 nm premodification to 1.7 nm postmodification on the surface-cleaned silicon. Similar experiments using oxide-coated silicon showed that the radical adsorbed to form much smoother layers, with a small change in rms roughness from 0.2 to 0.3 nm. Contact angle measurements of water on the premodified and postmodified samples showed a large, hydrophobic change in the silicon oxide surface but only a modest change in the surface-cleaned silicon surface. Samples of mNBA adsorbed onto silica gel showed strong electron-spin resonance signals from the aminoxyl spin, even years after production. The results demonstrate the prospects for treating and coating oxide-covered silicon wafers and silicon oxide-coated particles with a paramagnetically active organic substrate, without major chemical modification of the pretreatment surface; the resulting organic spin sites can be stable for years.

Anionic polymerization of 4-methacryloyloxy-TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidin-1-oxyl) was successfully carried out using methyl methacrylate-capped 1,1-diphenylhexyllithium (DPHLi/MMA), of which nucleophilicity is moderate enough to suppress the side reaction between the nitroxide radical of TEMPO moiety and the carbanion of DPHLi, to yield the radical polymer with well-controlled molecular weight, narrow polydispersity index (PDI < 1.10), high yield (>95%), and almost 1.0 radicals per monomer unit.

Poly(3,4-ethylenedioxythiophene) (PEDOT), for use as a hole-transporting layer in dye-sensitized solar cells (DSSCs), was synthesized via in-situ polymerization using a gas-phase oxidant. Highly volatile iodine was used as the gas-phase oxidant to fill up a porous TiO2 substrate. The conductivity of PEDOT increased to 0.9 S/cm upon the addition of a base, 4-tert-butylpyridine, to the monomer solution. A solid-state DSSC was fabricated using PEDOT as the hole-transporting layer, which displayed photo-electric conversion.

The interaction between 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin and different polycations is studied by UV-vis spectroscopy. Two polycations containing charged aromatic residues (imidazolium and pyridinium) have been easily synthesized by Paal-Knorr reaction of alternating aliphatic polyketones with histamine and 4-picolylamine. It was found that these polymers stabilize the tetra-anionic form of the porphyrin at acidic conditions, and avoid the formation of H- and J-type self-aggregates. Other polycations such as poly(allylamine) and poly(decylviologen) enhance porphyrin self-aggregation. As the latter polymer has also aromatic charged groups, the influence of the polymer structure as a whole in the behavior of the porphyrin/polycation system is highlighted. In this context, similar but not equal results have been found comparing the influence of the polyketone derivative containing pyridinium groups and the polycation poly(4-vinylpyridine) on the porphyrin self-aggregation and acid base behavior. (C) 2013 Elsevier Ltd. All rights reserved.

A poly(vinylsulfonic acid) (PVSA)-grafted poly(ether ether ketone) (PEEK) was simply prepared by one-pot, gamma-ray radiation-induced graft polymerization of the vinylsulfonic acid (VSA) solution dissolving PEEK. The VSA-highly-grafted PEEK membrane possessed high ion exchange capacity (e.g., 7.2 mequiv g(-1)) and showed proton conductivity in the order of 10(-1) and 10(-3)-10(-6) S cm(-1) under hydrated and nonhumidified conditions, respectively.

A highly cross-linked polyviologen hydrogel, poly(tripyridiniomesitylene) (PTPM), has been designed as an anode-active material. It displays a reversible two-electron redox capability at -0.4 and -0.8 V vs Ag/AgCl in an aqueous electrolyte. The PTPM layer coated on a current collector by electropolymerization via a 4-cyanopyridinium electro-coupling reaction demonstrates a rapid charging-discharging reaction with a redox capacity comparable to that obtainable using the formula weight-based theoretical density, because of the combination of the redox-active viologen moieties built into the hydrogel. A test cell that has been fabricated using the developed PTPM anode, a poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl acrylamide) (PTAm)-based cathode, and an aqueous electrolyte exhibits a discharging voltage of 1.1 and 1.5 V, and has proven its ability to be recharged more than 2000 times.

'Self-doping' inspired high-density redox copolymers were designed and prepared via free radical copolymerization of 2,2,6,6-tetramethyl-4-piperidyl methacrylate and vinylsulfonic acid (VSA) with a view to preventing a change in salt concentration during the one-electron oxidation of the nitroxide radicals to N-oxoammonium cations in a polymer layer. A copolymer composition of TEMPO-sulfonate anionic group = 1/1 for density-maximized charge neutralization was achieved by controlling the feed ratio of the copolymerization. The formation of copolymers was evidenced by 2D nuclear Overhauser enhanced spectroscopy (NOESY) and diffusion ordered spectroscopy (DOSY) NMR. Poly(TEMPO methacrylate-stat-VSA) was considered to have the alternating tendency due to the acid-base interaction in the comonomers, which were supported not only by the single crystal structure of the 2,2,6,6-tetramethyl-4-piperidyl methacrylate and VSA complex, but also by the 1H-1H correlation in NOE signals. In an aqueous electrolyte with 0.5 M NaCl, the copolymer electrode showed a redox response near 0.66 V (vs. Ag/AgCl), and the excellent cycle performance during 1000 cycles. During the one-electron oxidation of the nitroxide radical, anionic sulfonate groups led to charge compensation of the N-oxoammonium cation. Consequently, the copolymer electrode exhibited the cation migration, which was evidenced by mass-transfer analysis using an electrochemical quartz crystal microbalance (EQCM) technique. The copolymer could be applied as an aqueous electrolyte-type organic rechargeable device. Moreover, this design proposes the ultimate principle toward the strategy of maximizing energy density in organic charge storage devices. © The Royal Society of Chemistry 2013.

A hydrophilic radical polymer, poly(2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide) (PTAm), was synthesized via oxidation of the corresponding precursor polymer, poly(2,2,6,6-teteramethylpiperidine-4-yl acrylamide). Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride (NaCl), sodium tetrafluoroborate (NaBF4), and sodium hexafluorophosphate (NaPF6) to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4 (-1) displayed quantitative redox capacity beyond 1 mu m layer thickness and maintained the discharging capacity of 110 mAh g(-1) (97% vs. the calculated capacity) even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly(N-4,4'-bipyridinium-N-decamethylene dibromide) as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of > 2000 with high coulombic efficiency of > 95%.

Redox-active but highly durable nitroxide radicals, that is, 2,2,6,6-tetramethylpiperidinyl-4-oxy (TEMPO), enabled direct electrospinning of radical-containing polymers without additional processing aids (such as polymer blends, post-doping, or protection/deprotection) and produced redox-active fibrous membranes with high surface area. The solution rheological behavior of the TEMPO-substituted polymethacrylate was similar to the neutral conventional polymers, and electrospinning of the radical polymers yielded submicrometer-scaled fibrous membranes without any defects on the radical moiety. The obtained membrane exhibited stable redox response, leading to redox catalysts or electrode-active materials toward organic-based flexible rechargeable battery. Polymer Journal (2012) 44, 264-268; doi:10.1038/pj.2011.120; published online 7 December 2011

Grafted polyelectrolyte coatings were obtained by surface-initiated atom transfer radical polymerization on an aluminum surface. Their chemical composition was verified by X-ray photoelectron spectroscopy and Fourier transfer infrared spectroscopy. The morphology of grafted polymer coatings on an aluminium surface was studied by atomic-force and scanning electron microscopy and the possibility of adjusting its hydrophilic properties in wide range was established.

A layer of poly(2-vinylanthraquinone) on current collectors underwent reversible electrode reaction at 0.82 V vs Ag/AgCl in an aqueous electrolyte. A repeatable charging/discharging cycles with a redox capacity comparable to the formula weight-based theoretical density at the negative potential suggested that all of the anthraquinone pendants in the layer was redox-active, that electroneutralization by an electrolyte cation was accomplished throughout the polymer layer, and that the layer stayed on the current collector without exfoliation or dissolution into the electrolyte during the electrolysis. The charging/discharging behavior of the polymer layer in the aqueous electrolyte revealed the capability of undergoing electrochemistry even in the nonsolvent of the pendant group, which offered insight into the nature of the anthraquinone pendants populated on the aliphatic chain. Charging/discharging capability of air batteries was accomplished by using the polymer layer as an organic anode-active material. A test cell fabricated using the conventional MnO(2)/C cathode catalyst exhibited a discharging voltage at 0.63 V corresponding to their potential gap and a charging/discharging cycle of more than 500 cycles without loss of the capacity.

Charge/discharge processes of organic radical batteries based on the radical polymer's redox reaction should be largely influenced by the structure and the composition of the composite electrodes. AC impedance measurement of the composite electrodes reveals a strong correlation between the overall electron transfer resistance of the composite electrode and the material of the current collector, and suggests that the electric conduction to the current collector through the contact resistance should be crucial. We also find that the adhesion and the contact area between the composite electrode and the current collector strongly influence the contact resistance rather than the work functions and the volume resistivities of the composite electrode and the current collector. It is also confirmed that the charge/discharge performance of the composite electrode is related to the overall electron transfer resistance of the composite electrode. These results indicate that the charge/discharge performance of the radical battery is dominated by the interfacial electron transfer processes at the current collector/carbon fiber interface. In fact, the composite electrode which has a high adhesion to the current collector shows a small overall electron transfer resistance and an excellent charge/discharge performance. The rate performance would be much improved by suitably designing the interfacial structure including adhesion and contact area. (C) 2010 Elsevier B.V. All rights reserved.

Condensation of anthraquinone-2-carboxylic acid with poly(4-chloromethylstyrene) afforded a high-density redox polymer containing the anthraquinone pendants with reversible charge storage capability at negative potentials near -1V versus Ag/AgCl. Electrochemically reversible redox response of the polymer, which was ascribed to the reduction of the pendant group to the anion radical and the dianion, suggested that the polymer was sufficiently robust in these redox states for charge storage application. Immobilizing the anthraquinone groups on current collectors was accomplished by the use of the polymer which was swellable and yet insoluble in both aqueous and nonaqueous electrolyte solutions. Such properties allowed the accommodation of external cations from the electrolyte solution to permeate through the polymer layer for electroneutralization of the negative charge produced at the reduced state, which led to the repeatable charging and discharging cycles without degradation of the charge storage capacity. Exploration of the aqueous electrochemistry of anthraquinone, which had been inaccessible by the lack of the solubility of the conjugated and fused-ring molecule in H2O, became feasible by virtue of the swelling property of the polymer layer in the aqueous electrolyte. While negative charge was relatively difficult to be stored with redox polymers compared to the positive charge due to the enhanced reactivity in their reduced states and small varieties of the appropriate redox sites, the present polymer was characterized as the excellent organic electrode-active materials that operated at sufficiently negative potentials which was essential for the fabrication of entirely organic batteries. Copyright (C) 2011 John Wiley & Sons, Ltd.

Proton-conducting polyelectrolytes were prepared by densely grafting novel sulfonic acid polymers, poly(styrene-sulfamide acid) (PSA) and poly(vinylsulfonic acid) (PVS), on the azo-initiator-modified poly(ethersulfone) (PSU). The grafted PSUs provided both a high ion-exchange capacity (IEC) and a good membrane formability. The proton-conductivities of the PSA-g-PSU and PVS-g-PSU membranes were 8.2 and 21mS cm(-1), respectively, at 90 degrees C under a hydrated condition, and 4.1 and 1.7mS cm(-1), respectively, at 150 degrees C under a nonhumidified condition. The latter conductivities were significantly higher than that of Nafion (R) 117 (0.03mS cm(-1) at 150 degrees C), which was ascribed to both the strong acidity of the graft chains even under the water-free state and the high IEC of the densely grafted membrane. They remained constant for over 1 week at 150 degrees C. Copyright (C) 2011 John Wiley & Sons, Ltd.

Gas diffusion layer (GDL) is an important component for the performance of polymer electrolyte fuel cells controlling the gas flow and the water transport. In this study, the real-time formation process of water droplets on two GDLs with different pore sizes was imaged using a CCD camera during the cell operation. A porphyrin luminescent dye was coated on the GDLs to clarify the shape of the water droplets. On the GDL with a smaller pore size, the droplets were distributed uniformly on the GDL in the flow channel at the cathode. On the GDL with a larger pore size, the water droplets were larger and formed mainly near the ribs of the flow channel, and the droplets were observed to move slowly towards the gas outlet. The difference in the formation of water droplets were explained by the difference in the partial air flow inside the GDLs along the gas channel.

Poly(vinylsulfonic acid) (PVS) possesses a high acid content (ion-exchange capacity in the chemical formula 9.2 meq . g(-1)). Its monomer, vinylsulfonic acid (VSA), had a high acid dissociation ability (Hammett acid function 0.74 in water), and a high ionic conductivity (0.04-0.11 S . cm(-1)). The radical polymerization of VSA with various initiators was kinetically investigated. The ESR spectrum of the VSA polymerization mixture showed a strong signal ascribed to the propagation carbon radical of VSA. The molecular weight of PVS increased with the increasing monomer concentration and decreasing radical initiator concentration to yield the PVS with a molecular weight of 4.0 x 10(4). Proton-conductivity of PVS under hydrated and nonhumidified conditions was on the order of 10(-1) and 10(-3)-10(-6) S . cm(-1), respectively.

The electrochemical redox reactions of organic polymers bearing robust unpaired electrons were investigated to determine the applicability of these polymers to rechargeable batteries. Such an "organic radical battery" would be environmentally friendly and have high-power characteristics. This highlight review describes the performance of a battery using a nitroxyl radical polymer as the cathode active material. The electron-transfer mechanism and recent developments that should lead to the practical application of the organic radical battery are also described.

Visualization inside polymer electrolyte fuel cells (PEFCs) is important for elucidating reaction distributions to improve the performance and durability of the cells. An O(2)-sensitive porphyrin luminescent dye film was used to visualize oxygen partial pressures and water blockages simultaneously in triple-serpentine gas flow channels in an operating PEFC. Water droplets formed near the exit of a gas-flow channel lowered the oxygen partial pressure noticeably over the channel by blocking air flow near the entrance. Meanwhile, air was continuously supplied from the other channels through the gas diffusion layer, thus allowing power to be generated in the blocked channel. With water blockages, however, the catalyst layer under the channel became flooded by the water produced during the reaction, and the flooded state continued to exist in the catalyst and/or porous layers, even after blowing the water droplet out, so that the power generation was lowered along the channel. (C) 2010 Elsevier B.V. All rights reserved.

During start-up/shut-down processes of a polymer electrolyte fuel cell, platinum particles are lost from the catalyst layer at the cathode due to corrosion of the carbon supports. We simulated the start-up/shut-down cycle by exchanging gases at the anode between hydrogen and air. During the gas exchange, the distribution of oxygen partial pressures at the anode was visualized by our real-time/space visualization system, which clearly showed the location of H-2- and O-2-rich areas along the gas-flow channel from the inlet to the outlet. The gas exchange rate was found to be much slower than that predicted from the simple replacement and to be correlated to the proton transfer derived from carbon corrosion of the cathode catalyst layer. By the visualization results, it was found that the shut-down process gives more serious effect than the start-up process. After the degradation, the oxygen partial pressure at the cathode was visualized during the cell operation. Oxygen was consumed mainly in the middle of the MEA because the MEA was degraded mainly near the inlet and outlet of reactant gases in the cell. (C) 2010 Elsevier B.V. All rights reserved.

An electrode-attached layer of poly(phenylacetylene) bearing a pendant nitronyl nitroxide group per repeating unit, obtained by the Rh-catalyzed polymerization of 2-(4-ethynylphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, underwent oxidation and reduction at 0.80 and 0.84 V vs. Ag/AgCl, respectively. The magnetically determined unpaired electron density of 92% was coulometrically reproduced, which supported the presumption that the radical survived during the course of the polymerization to allow both positive and negative charging of the pristine neutral polymer substantially per repeating unit. Galvanostatic Coulomb titration revealed the charge storage capability of the polymer, which demonstrated usefulness as organic electrode-active material with unprecedented ambipolar chargeability.

The ring-opening polymerization of 5-methyl-1,3-dioxolane-2,4-dione (lactic O-carboxylic anhydride, LacOCA) using organometallic complexes, including Co(III) complexes with Schiff base ligands, Tin(II) alphatates and Al(III) complexes with Schiff base ligands, was explored. The polymerization was carried out by treatment of the organometallic complexes with LacOCA in toluene under mild conditions. The corresponding poly(lactic acid) was characterized by spectroscopy and thermal analyses, which revealed insight into the structure of the effective catalyst for the polymerization of LacOCA.

A luminescent PtTFP/PMSP polymer coating was prepared for the oxygen partial pressure visualization inside a PEFC. PMSP formed a smooth and tough coating as a highly oxygen-permeable matrix with a thickness of ca. 2 mu m in which the PtTFP was homogeneously dispersed. The coating displayed a strong red luminescence with significantly decreasing intensity upon increasing oxygen partial pressure. The sensitivity for the oxygen partial pressure was high and the analytical curve of the sensor polymer coating was undisturbed by external factors. The PtTFP/PMSP sensor was coated on the surface of a cathode gas diffusion layer on the air flow channel inside PEFC. The oxygen-pressure distribution in the air flow channel was successfully visualized while operating the PEFC.

We describe the capsulation of colloidally templated polythiophene (P3-TAA) arrays with multi-walled carbon nanotubes (MWNTs) after colloidal template electropolymerization. The dissolution of the polystyrene (PS) particle templates, which were assembled via the Langmuir-Blodgett (LB)-like technique, allowed the formation of hollow-shell Janus type arrays.

To maximize the theoretical redox capacity of polymers containing cyclic nitroxides as redox active pendant groups for high density charge storage application, a compact five membered ring with the smallest equivalent weight among the robust cyclic nitroxides was directly bound to a poly(ethylene oxide) chain 2,2,5,5 Tetramethyl 3 oxiranyl-3-pyrrolin 1 oxyl was synthesized and polymerized via anionic coordinated ring-opening polymerization utilizing diethyl zinc/H2O as an initiator The unpaired electron in the monomer survived during the polymerization giving rise to a high density redox polymer with a weight-specific theoretical capacity of 147 mA h/g Cyclic voltammetry of the polymer layer confined at the surface of an electrode revealed a large redox capacity comparable to the theoretical capacity which was ascribed to the efficient swelling and yet insoluble properties of the polyether in electrolyte solutions by virtue of the high molecular weight of >10(5) and adhesive properties allowing immobilization of the layer on the electrode surface The redox capacity also indicated that the ionophoric polyether matrix accommodated electrolyte anions through the polymer/electrolyte interface to neutralize positive charges produced by the oxidation of the neutral radicals at the polymer/electrode interface The diffusion coefficient for the redox gradient driven charge hopping process corresponded to a large second order rate constant in the order of 10(7) M-1 s(-1), which suggested an efficient electron self-exchange reaction throughout the polymer layer due to the large redox site population and hence to the small intersite distance Test cells fabricated with a polymer/carbon fiber composite layer on an aluminum current collector as the cathode and a Li anode sandwiching an electrolyte layer were capable of charging and discharging as a secondary battery with an output voltage near 3 7 V and were durable for more than 10(3) charging discharging cycles without substantial degradation

We present here the synthesis of two kinds of amphiphilic block copolymers, a diblock copolymer MPEG-b-PTAm and a triblock copolymer MPEG-b-PLA-b-PTAm, which can self-assemble into micelles with nitroxyl radicals-containing PTAm segment in the core. The structure of the block copolymers was characterized by H-1 NMR and GPC. Dynamic laser light scattering and transmission electron microscopy were used to study the micellar behavior of the two block copolymers in aqueous solution. The micelles carrying nitroxyl radicals in the core can generate electron paramagnetic resonance, which is stable for a period of time up to 8 min even in the presence of reducing reagent such as ascorbic acid. The enhanced stability against the reducing agent was ascribed to the inaccessibility of the nitroxyl radical core placed in the interior of the micelles. Combined with the biocompatibility, these micelles were promising to be used as the EPR probes for bioimaging in vivo. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5404-5410, 2010

Active control of flow over object surfaces achieved by means of mechanical and/or electrical methods has recently been studied. However, there has been no report on actively switching the surface drag of an object by chemical modification of the object's surface. Poly(N-isopropylacrylamide) (PNIPA) was grafted onto the surface of an aluminium (Al) substrate via (A) surface-initiated atom transfer radical polymerization and (B) radical polymerization with an azo-group surface initiator. The grafting density was 0.19 and 0.15 chains nm(-2), respectively. The water contact angle of the PNIPA-grafted Al surface reversibly changed between 55 and 82 for (A) and between 42 degrees and 65 degrees for (B) at temperatures of 25 and 40 degrees C, which was ascribed to the temperature-responsive, hydrophilic-hydrophobic switching of the grafted PNIPA surface. The PNIPA grafting was applied on the surface of an ogive-shaped Al model. The normalized dropping speed of the model in water increased 1.1 times at 42 degrees C in comparison to that at 22 degrees C. Switching of the surface drag of PNIPA-grafted Al in water was demonstrated on the basis of the hydrophilicity and hydrophobicity of the grafted Al surface, the switching occurring with a change in temperature. (C) 2010 Society of Chemical Industry

Copolymers composed of PLA and PTAm were prepared by a macromonomer approach. The PLA bearing vinyl group at chain end was copolymerized with 2,2,6,6-tetrametylpiperidine-4-ylacrylamide. The resulted copolymers were oxidized by a peroxide to give PTAm-g-PLA. The structures of the copolymers were confirmed by NMR and FTIR spectroscopy. The comparison of (1)H NMR results and SQUID measurements demonstrated that the oxidation of the PTAm fragment proceeded almost to completion. An MTT assay, cell adhesion and spreading evaluation showed that the copolymers exhibited improved cytocompatibility as compared to the PTAm homopolymer due to the introduction of the biocompatible PLA moiety.

Luminescent oxygen-sensory polymer-coatings composed of platinum tetrakis(pentafluorophenyl)-porpholactone (PtPL) and -porphyrin (PtPP) with poly(trimethylsilylpropyne) (PMSP) were prepared for visualization of the oxygen partial pressure on two parallel planes or a biplanar surface. PMSP formed a smooth and tough coating as a high oxygen-permeable polymer matrix with a thickness of ca. 2 mu m, which homogeneously contained the luminescent dye probe. PtPL or PtPP. Under UV light (395 nm) irradiation, the coatings displayed strong magenta and red luminescence with maximum peaks at 750 and 650 nm ascribed to the PtPL and PtPP, respectively. The luminescence of the two coatings was efficiently quenched by oxygen which allowed the development of engineering curve to analyze the oxygen partial pressure. The luminescence intensities of the two coatings were separately monitored in order to allow the simultaneous measurement of the oxygen partial pressure distribution upon two planar surfaces. (C) 2010 Elsevier Ltd. All rights reserved.

A multiply-fluorinated cobalt phthalocyanine (CoFPC) was prepared, which could reversibly interact with oxygen. CoFPC was introduced into the hydrophobic perfluoroethylene-backbone domain of the Nafion membrane. The localization of CoFPC did not reduce the high proton conductivity (10(-2)-10(-3) Scm(-1)) ascribed to the hydrophilic channel of Nafion. The oxygen permeability through the CoFPC/Nafion membrane was higher than the nitrogen permeability and that of the pristine Nafion membrane, and was significantly enhanced at the lower upstream pressure. The permselectivity of oxygen versus nitrogen increased beyond 20 with the CoFPC content in the membrane. The CoFPC/Nafion membrane was coated on a glassy carbon modified with a Pt/C catalyst. The high electrochemical reduction current of oxygen suggested that the CoFPC/Nafion membrane efficiently supplied oxygen to the Pt/C catalyst. Copyright (C) 2009 John Wiley & Sons, Ltd.

The interaction between rhodamine 6G and different polyelectrolytes is analyzed. Structural aspects differentiate these polyelectrolytes, such as the presence of aromatic groups and the number and localization of their respective charges, which may be directly attached to the aromatic groups or to the polymeric main chain. In the case of poly(sodium acrylate), which does not bear aromatic groups, the polyelectrolyte induces cooperative self-stacking between the dyes which is highly sensitive to the ionic strength, due to the predominance of long-range electrostatic interactions between the polymer and the dye. In the case of poly(sodium 4-styrenesulfonate), whose charge is directly attached to the aromatic groups, a high dispersant ability of the dyes is found and the interaction is less dependent on the ionic strength, due to the predominance of short-range aromatic-aromatic interactions between the dye and the polymer. Among the two polyelectrolytes studied for which the polymeric charge is directly attached to the main chain, and separated from the aromatic group, poly(styrene-alt-maleic acid) shows a lower dependence of the interaction on the ionic strength than poly(N-phenylmaleimide-co-acrylic acid) at a comonomer composition of 1:2, due to a higher linear aromatic density and a lower linear charge density, indicating the importance of hydrophobic forces. Both copolymers exhibit a high ability to induce cooperative self-aggregation of the dye.

Purely organic high-spin poly(aminium cationic radical)s of two-dimensionally extended soluble aromatic polyamines P1 and P2 were prepared by the palladium-catalyzed polycondensation of two multifunctional monomers, followed by chemical or electrochemical oxidations. The chemical structures of the precursor polyamines were fully characterized by (1)H-and (13)C nuclear magnetic resonance (NMR), infrared and MALDI-TOF mass spectra (MS). The aminium radical sites of N,N,N',N'-tetraaryl-p-phenylenediamines were connected through the m-phenylene ferromagnetic coupler, which satisfies the non-Kekule-type molecular design. Oxidation of radical sites was facilitated by electron-donating methoxy substituents. The first oxidation potential (E degrees'(1)) of P2 with methoxy substituents, evaluated from the cyclic voltammograms in CH(2)Cl(2), was 0.69 V (vs Ag/Ag(+)), whereas the E degrees'(1) of P1 without electron-donating substituents was 0.78 V. This result was further verified by spectroelectrochemistry measurements. The electrochemically oxidized P2 displayed a more intense low-energy band at ca. 800 nm ascribed to aminium cationic radicals and bications. Chemical oxidation of P1 and P2 with NOPF(6) solubilized with 18-crown-6 in CH(2)Cl(2) gave the corresponding poly(aminium cationic radical) s. The high-spin ground states were confirmed by the temperature dependence of forbidden electron spin resonance (ESR) transition peak intensities, and the average spin quantum number (S) determined by the magnetic curves reached 8.4/2 at low temperatures. Remarkably, when a small amount of trifluoroacetic acid was added, the half-life of polyradicals reached ca. 1 week at room temperature (RT). This result prompted us to observe the single polymer-based molecular and magnetic images by atomic force microscopy and magnetic force microscopy, respectively. The precursor polyamine P1 showed globular-shaped polymer particles with an average vertical distance of 1.43 nm. After chemical oxidation, the vertical distance of P1 definitely decreased, reflecting the improved p-type character of the nitrogen atoms. Moreover, the detection of weak MFM images supported the presence of magnetic spins in the single polymers. Polymer Journal (2010) 42, 575-582; doi:10.1038/pj.2010.47; published online 26 May 2010

Charge/discharge processes of organic radical batteries based on the radical polymer's redox reaction are largely influenced by carbon fibers consisting in the composite electrodes to help electron transfer. To find the optimal structure of the composite electrodes, the dominant electron transfer processes were determined by ac impedance measurement of the composite electrodes. A strong correlation between the overall electron transfer resistance of the composite electrodes and the materials of the current collector suggests that the electric conduction to the current collector through the contact resistance should be crucial. It was also confirmed that the charge/discharge performance of the composite electrode was related to the overall electron transfer resistance of the composite electrode. These results indicated that the charge/discharge performance of the radical battery was dominated by the interfacial electron transfer processes at the current collector/carbon fiber interface and that the rate performance would be much improved by suitably designing the interfacial structure.

The polyaromatic-ion behavior of poly(sodium N-maleoyl-2-aminobenzoate-co-sodium acrylate) in a comonomer composition 1:2, poly(sodium N-maleoyl-4-aminobenzoate-co-sodium acrylate) in a comonomer composition 1:2, and poly(sodium N-maleoyl-4-aminobenzoate-co-N,N-dimethylacrylamide) in a comonomer composition 1:1 is studied. The copolymers undergo short-range aromatic aromatic interactions with methylene blue and rhodamine B, as a consequence of which their UV vis monomer band is shifted to lower energies. As a result of their polyaromatic-anion behavior, methylene blue is easily dispersed on the polymeric domains. Moreover, the pK(a) of rhodamine B is shifted from 3.2 to 4.5-5 in the presence of these copolymers. This behavior is also observed in the presence poly(sodium 4-styrenesulfonate), but not in the presence of poly(sodium vinyl sulfonate), which are taken as reference polymers. Compared with poly(sodium 4-styrenesulfonate), a lower resistance to the cleaving effect of added NaCl on the interaction with methylene blue is found. A different influence on the reduction of 2,3,5-triphenyl-2H-tetrazolium chloride with ascorbic acid was found for the different polyelectrolytes.

A robust nitroxide radical, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its 4-subsituted derivatives (R-TEMPO) exhibit electrochemically reversible redox properties with tunable half-wave potentials (E-1/2) based on the substituent effect. Dye-sensitized solar cells using R-TEMPO as mediators with electron-withdrawing R groups showed significantly enhanced photovoltages compared with those obtained using iodides. The linearity between the open-circuit voltage (V-oc) and E-1/2 revealed that V-oc dominated by the energy gap between the Fermi level of TiO2 and the SOMO level of R-TEMPO.

The aggregation of methylene blue around different polyelectrolytes is studied by diafiltration, UV-vis, and (1)H NMR spectroscopies. Poly(sodium acrylate-co-sodium maleate) induces the formation of higher-order aggregates, showing a typical polyelectrolyte behavior dominated by long-range electrostatic interactions with the dye which are highly dependent on the ionic strength. Poly(sodium 4-styrenesulfonate) presents a high dispersant ability of methylene blue, showing what we can call a typical polyaromatic-anion behavior characterized by the presence of short-range aromatic-aromatic interactions with the dye which are less dependent on the ionic strength. An intermediate behavior is found for the copolymers poly(sodium 4-styrenesulfonate-co-sodium Maleate) at two different comonomer compositions, related to a different probability of the polymers to form and stabilize ion pairs in hydrophobic environments. Their behavior is a function of the linear aromatic density, which is related to the comonomeric Structure.

A quartet triradical molecule, 2,6,10-tris[bis(p-methoxyphenyl)aminium]triphenylene, was characterized by the electronic interaction among the three aminium sites based on the fused-aromatic, triphenylene-linked, and non-Kekule connectivity, which lead to the stable high-spin triradical formation.

A series of cobalt complexes with N,N,O,O-tetradentate Schiff base ligands were prepared. All the complexes were characterized by spectroscopy and electrochemical methods. An X-ray crystal structure analysis revealed that L-1-Co-III-dnp was monomeric with a six-coordinated central cobalt(III) atom in the solid state. The complexes were employed as catalysts for the alternating copolymerization of CO2 and racemic propylene oxide. End group analysis of the resulting polymer provided strong evidence for a monomer insertion mechanism for the propagation step. The catalytic activity was interpreted using the redox potential of cobalt(II/III) for the L-Co-III-dnp complexes, which offered a measure of the bond strength, or the degree of inertness of the axial ligand, to promote or suppress the monomer insertion.

The reversible n-type charge-storage capability of polyimides was significantly enhanced in a polyimide/carbon nanocomposite prepared by cyclodehydration of the corresponding polyamic acid which was solution-processed into a composite layer on an electrode surface with a vapor-grown carbon nanofiber. The stepwise preparation process gave the first polyimide-based electrode-active material with a sufficient dispersion of the polyimide particles at the carbon nanofiber surface, while a simple grinding of the polyimide and the carbon nanofiber gave mixtures without charge retention capability due to gradual dissolution in the reduced state. The polyimide/carbon nanocomposites were characterized by negative redox potentials at -1.36 and -0.76 V vs. Ag/AgCl for poly(4,4'-oxydiphthalimido-1,4-phenylene) (1) and poly(pyromellitimido-1,4-phenylene) (2), respectively, which corresponded to a charging per repeating unit of the neutral polymers to radical polyanions. The 2/carbon nanocomposite underwent further reduction at -1.34 V to produce a dianion per repeating unit, giving rise to a high-density charging with a redox capacity of 185 mAh g(-1) based on the formula weight of 2. The typical redox capacity of the electrolyzed nanocomposites amounted to ca. 60% of the formula weight-based capacity, which was still larger than those of typical redox polymers with negative potentials, such as viologen-based polyelectrolytes. Additional advantages originated from the robustness of the polyimide framework, which allowed excellent charging/discharging cyclability. The polyimide/carbon nanocomposite electrodes would be highly promising as anode-active materials in organic rechargeable devices, owing to these excellent redox properties.

Electrochemically oxidized patterns of stable poly(nitroxide radical)s at the nano-scale were demonstrated by controlling lithographic parameters, such as voltage, scan speed, and sweep duration.

Poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl acrylamide) was designed and synthesized as an electrode-active polymer for an organic rechargeable device containing an aqueous electrolyte. The device demonstrated a 1.2 V output voltage, exceeded 2000 charging-discharging cycles, and had a high charging rate performance within 1 min.

The synthesis, characterisation and application of novel high-density poly(vinylsulfonic acid)-grafted solid acid catalysts are described. A graft, radical polymerization procedure was employed, allowing the immobilisation of the acid form of vinylsulfonic acid monomer onto various carrier materials, such as polystyrene, silica or polysaccharide-based gels. The highest acid-exchange capacity (as determined by acid-base titration methods) achieved with these new materials was 5.2 mmol H+ g(-1). The properties of these PVS-grafted materials as solid state acid catalysts have been examined from several perspectives, including their fundamental properties as materials with extremely high acid dissociation characteristics, their structural features as revealed from IR and solid-state NMR measurements, their thermal stability properties, and their surface morphologies, humidity dependencies and functionality. Compared to many other types of acid catalysts, these high-density poly(vinylsulfonic acid)-grafted materials demonstrated superior catalytic performance in esterification, Friedel-Crafts acylation, and condensation reactions. Moreover, these novel materials show high stability, significant anticorrosion capability and can be easily recycled.

Highly and homogeneously crosslinked poly(beta-ketoester) networks densely bearing robust nitroxide radicals were prepared via a click-type and stepwise Michael polyaddition. A half-battery cell composed of the thermally-cured radical network coatings displayed a rapid, reversible, and almost stoichiometric redox-activity even with a thickness of ca. 10 mu m, which may be applicable as the electrode of organic-based rechargeable devices.

Two redox-active poly(oxoammonium salt)s were synthesized via chemical oxidation of a TEMPO-substituted polymer, or conventional radical polymerization of the oxoammonium monomer, respectively. The diode-structured thin film device composed of poly(oxoammonium salt) with radical conc. of 6-43% exhibited a resistive switching behavior (ON-OFF ratio > 10(3)), in contrast to the radical-free poly(oxoammonium salt), which revealed that the coexistence of radical/oxoammonium salts contributed to a significant change in I-V characteristics.

Luminescent oxygen sensory polymer coatings composed of platinum tetrakis(pentafluorophenyl)porpholactone and -porphyrin with poly(trimethylsilylpropyne) were prepared. Two luminescence peaks at 750 and 650 nm from the coating ascribed to the porpholactone and the porphyrin, respectively, were efficiently quenched with oxygen and were separately monitored to allow the simultaneous measurement of oxygen partial pressure distribution upon two planar surfaces.

A radical polymer is an aliphatic organic polymer bearing densely populated unpaired electrons in the pendant robust radical groups per repeating unit. These radicals' unpaired electrons are characterized by very fast electron-transfer reactivity, allowing reversible charging as the electrode-active materials for secondary batteries. Organic-based radical batteries have several advantages over conventional batteries, such as increased safety, adaptability to wet fabrication processes, easy disposability, and capability of fabrication from less-limited resources, which are described along the fashion of green chemistry.

A hydrophilic poly(vinyl ether)-backbone polymer bearing a pendant TEMPO radical, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl vinyl ether) (PTVE), was designed as a cathode-active material, which displays a reversible one-electron redox capability, even in an aqueous electrolyte. The PTVE layer coated on a current collector demonstrated a rapid charging-discharging rate based on the combination of the redox-active nitroxide radicals built into the hydrophilic polymer and the aqueous electrolyte that possessed a high electrical conductivity. A test cell fabricated with a PTVE cathode, a zinc anode, and an aqueous electrolyte gave an output voltage of 1.7 V and showed the ability to be recharged more than 500 times rechargeability.

This article describes the synthesis of the two-dimensionally extended aromatic polyamines by polycondensation between the tri-sec-amine monomer and p-phenylenediamine-based dibromide, the polyradical generation by chemical and electrochemical oxidations, and the hole-transporting properties. The molecular weights (M(n)) of the polyamines, 3a and 3b, were 7700 and 5000, respectively, and both polymers were very soluble in the typical organic solvents, ensuring a good film formation capability by a spin-coating technique. The thermal stability of the aromatic polyamines, elucidated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), was quite high. More important, the cross-conjugated structure is essential for the controlled radical generation and the maintenance of the radical stability. Cyclic voltammograms of the neutral polyamines in the presence of 1 vol % of trifluoroacetic acid and the intervalence bands of the partially oxidized polyamines with NOPF(6) revealed that the generated radicals delocalize over the p-phenylenediamine moieties. The half-life of the polyradicals was about 12 h even under ambient conditions, which allowed us to fabricate and measure the hole-only devices. The charge-tran sporting properties of the polyamines were dramatically changed by the partial oxidation (20 mol %/aminium unit) with NOPF(6). The neutral polyamines showed the conventional injection-limit behaviors, whereas the hole-transporting behaviors of the polyradicals are bulk-limit and highly dependent on the chemical structure. The efficient hole-transport of the all-conjugated poly(aminium cationic radical)s was for the first time realized for the polyradical of 3b. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4577-4586, 2009

The aggregation behavior of C.I. Basic Violet 10 in the presence of poly(sodium 4-styrenesulfonate) was modified, as a consequence of short-range interactions. In aqueous acidic media, the cationic dye forms hydrophobic ion pairs with polymeric benzene sulfonate groups which tend to aggregate in H-contacts, this tendency being readily influenced by the relative concentration of the macromolecule with respect to that of the dye. In the case of dilute aqueous dye solutions (<= 10(-4) M), for which the probability of dye self-aggregation is small, C.I. Basic Violet 10 self-contacts are forced in the presence of a moderate excess of poly(sodium 4-styrenesulfonate). At dye concentrations > 10(-4) M, for which the probability of dye self-aggregation increases, dye-dye contacts are minimized in the presence of a large excess of the polymer. Hence, the luminescence of dye solutions can be tuned insorar as, that of dilute dye solutions is quenched whilst that of concentrated dye solutions can be enhanced. This behavior was not observed for other polyelectrolytes such as poly(sodium vinylsulfonate), or the more hydrophobic poly(sodium 2-(N-acrylamido)-2-methyl-propanesulfonate). (C) 2009 Elsevier Ltd. All rights reserved.

A triple-layered luminescent polymer coating was prepared to simultaneously detect both oxygen and temperature upon the coating. The coating was composed of an oxygen and a temperature sensory layer based on platinumporphyrin (PtTFP) and ruthenium phenanthroline (Ru(phen)) dye molecule, respectively. The temperature-sensitive Ru(phen) was dispersed in gas-barrier polyvinyl alcohol as the first layer, which was further coated with a water-proofing fluorine-containing polymer. The oxygen sensory layer composed of the oxygen-sensitive PtTFP and high oxygen-permeative poly(1-trimethylsilyl-1-propyne) was coated as the third layer. The two luminescences were separately monitored: the oxygen partial pressure and temperature in the range of 0-21 kPa and of 25-120 degrees C were successfully detected.

The interaction between methylene blue (MB) and poly(sodium 4-styrenesulfonate) (PSS), poly(sodium vinylsulfonate) (PVS), and the more hydrophobic poly[sodium 2-(N-acrylamido)2-methyl-propanesulfonate] (PAMPS), is investigated. The main driving forces for the interaction with PSS are supposed to be short-range aromatic/aromatic interactions, which explain the smaller dissociation constant, the resistance to the cleaving effect of NaCl, and the prevention of MB self-aggregation around the macromolecules under a moderate excess of the polymer. On the contrary, as a consequence of long-range interactions, a higher local concentration of MB around PAMPS and, more significantly, around PVS results in MB self-aggreation that can be g quenched in the presence of NaCl.

Radical polymers are aliphatic or nonconjugated polymers bearing organic robust radicals as pendant groups per repeating unit. A large population of the radical redox sites allows the efficient redox gradient-driven electron transport through the polymer layer by outer-sphere self-exchange reactions in electrolyte solutions. The radical polymers are emerging as a new class of electroactive materials useful for various kinds of wet-type energy storage, transport, and conversion devices. Electric-field-driven charge transport by hopping between the densely populated radical sites is also a remarkable aspect of the radical polymers in the solid state, which leads to many dry-type devices such as organic memories, diodes, and switches.

Chiral poly[4,6-bis(alkylthio)-1,3-phenylene-alt-2-methyl-1,3-phenylene] was synthesized from 1,3-dibromo-2,6-bis(3-dodecyl-2-methylthio)benzene and 2-methyl-1,3-phenylenebis(pinacol borate) as a precursor of chiral poly(thiaheterohelicene). Circular dichroism (CD) spectra that arise from the poly(1,3-phenylene) backbone inverted according to the chirality of the side chains, which indicated that a helical conformation of the polymer was induced by the interaction between the side chains. The CD intensity of the polymer increased in non-polar solvents such as hexane. The decrease in the molar CD intensity and the broadening of a fluorescence band at higher concentrations Suggested that the aggregation of the polymer Suppressed the formation of the helical structure. The conformational changes were monitored by the CD and the (1)H NMR spectra at different temperatures. In a good solvent Such as dichloromethane, the CD intensity increased, and the (1)H NMR signal of benzene protons shifted to lower fields at low temperatures. In hexane. the CD spectra and the I H NMR signals were less dependent on temperatures, as a result of the strong interaction between the chiral alkyl chains in the polymer to freeze the helical conformation. (C) 2009 Elsevier B.V. All rights reserved.

2,6,10-Tris[5'-(5-hexyloxyphenyl-2,2'-bithiophenyl)]-3,7,11-tris(hexyloxy)tripheneylene (2) was designed and synthesized as a pi-conjugated platform to produce its tris(cationic radical) derivative (1) in a non-Kekule and nondisjoint fashion. An electrochemical study revealed the chemically reversible redox property of 2. Gaseous antimony pentachloride-doping of 2 dispersed in a polystyrene matrix gave its cationic radical. It was chemically stable with a half-life >2 weeks and displayed a triplet ground state based on an ESR measurement. A high-spin state with S=3/2 for 1 was proved by the magnetization and magnetic susceptibility. (C) 2009 Elsevier B.V. All rights reserved.

A vinylpyridine block copolymer was prepared by stepwise controlled/living radical polymerization with a novel bifunctional initiator, 4-(2-bromopropanoyloxy)-N-(p-methylbenzyloxy)-2,2,6,6-tetramethylpiperidine. The initiator was synthesized in a facile manner using commercially available p-xylene and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4-hydroxy TEMPO). Through stepwise atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and nitroxide-mediated radical polymerization (NMRP) of 4-vinylpyridine (4VP), the PMMA-b-P4VP copolymer was prepared with a wide range of the copolymer compositions. Microphase-separation was demonstrated in cross sectional TEM images of self-standing block copolymer membranes.

The novel gold nanoparticle, which was stabilized with pi-conjugated molecules bearing functional groups at the terminals, was prepared via conventional procedure by using 5-bromo-2,2'-bithiophene-5'-thiol as a stabilizer. The gold nanoparticle (ca. 3 nm-diameter) showed good dispersion stability in various organic solvents, and its electrochemical and spectroscopic study revealed peculiar properties originated in the pi-conjugated molecular stabilizer, bithiophene derivative. The Pd-catalyzed coupling reaction on the gold nanoparticle was first achieved by using the gold nanoparticle bearing bromo groups at the particle surface and the model boronic acid molecule, 5-formyl-2-thiopheneboronic acid, to yield the terthiophene derivatives on the gold nanoparticle. The (1)H-NMR, UV, and TGA analysis supported the progress of the coupling reaction on the gold nanoparticle. This Pd-catalyzed coupling reaction was applied with the borate-terminated polythiophene to form polythiophene/gold nanoparticle alternate network film. The electron microscopic images supported the formation of the network structure. The high electric conductivity on the network film suggested that the conductive characteristic of the film originated from that of the pi-conjugated polythiophene backbone connected with the gold nanoparticle.

A hydrophilic radical polymer electrode-based rechargeable battery was designed along the concept of green chemistry. A hydrophilic radical polymer, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl vinylether), was synthesized as an electrode-active material; its battery demonstrated a high charging-discharging rate and long cycle life. The combination of the hydrophilic polymer electrode and an aqueous electrolyte for the battery fabrication was expected to provide safety improvements such as a low ignition risk besides the high battery performance. The green characteristics were studied using the "i-Messe," an evaluation method proposed by the committee of the Green Sustainable Chemistry Network, Japan. The electrode-active polymer was evaluated for substantial improvements in disaster safety and health safety.

A film of poly( 2,2,6,6-tetramethylpiperidinyloxy-4-yl vinylether) coated on a current collector displayed a rapid and reversible electrochemical response in aqueous electrolytes, and allowed an ultrafast full charging of 3 mC cm(-2) in as short as 3 seconds by virtue of the combination of the hydrophilic radical polymer and the aqueous electrolyte possessing a high electrical conductivity.

A high-density sulfonic acid polymer, grafted onto a carrier surface, was synthesized from the acid form of vinylsulfonic acid monomer, and its catalytic activity as a new class of heterogeneous acid catalyst demonstrated in esterification reactions.

A Nafion membrane containing a cobaltporphyrin (CoP) complex as a fixed oxygen carrier was prepared with a view to facilitate oxygen transport through the membrane. The design concept of the CoP-loaded Nafion membrane was based on the CoP's modification to place the CoP complex in a hydrophobic domain of the microphase-separated structure, in order to facilitate the oxygen transport and to maintain proton conductivity. The oxygen permeability through the CoP-loaded Nafion membrane was higher than the nitrogen permeability, and significantly enhanced at relatively-low oxygen pressures of the upstream, indicating that the fixed Col? complex acted as an oxygen hopping site to facilitate the oxygen transport. The oxygen/nitrogen permselectivity increased with the content of CoP in the Nafion membrane. Electrochemical reduction of oxygen at a glassy carbon electrode, modified with a Pt/C catalyst and the CoP-loaded Nafion membrane, provided additional support for the facilitated oxygen transport by the membrane. Increased current for the reduction of oxygen on the modified electrode by loading CoP indicated that the CoP offered the oxygen hopping site in the Nafion membrane. (c) 2008 Elsevier Ltd. All rights reserved.

Poly[1-trimethylsilyl-1-propyne-co-1-(3-pyridyl)propyne] 1 was prepared both as a polymer-ligand of a palladium porphyrin (PdOEP) and of a platinum porphyrin (PtTFP) and as a highly gas-permeable polymer matrix of the porphyrin. The porphyrin acted as a phosphorescence probe which could be quenched with oxygen and sense the oxygen partial pressure. 1 gave a smooth and tough coating with a thickness of ca. 2 mu m which homogeneously involved the porphyrin. The porphyrin-1 coatings displayed strong red-colored phosphorescences (the emission maximum at 670 and 650nm for PdOEP and PtTFP, respectively), and their intensity significantly decreased with an increase in the oxygen partial pressure on the coating. The high oxygen-quenching efficiency or the high oxygen pressure sensitivity of the porphyrin's phosphorescence was observed even at cryogenic temperature. Aggregation of the porphyrin was suppressed in the coating by ligation of the porphyrin with the nitrogenous residue of 1 to significantly reduce spatial noise in the phosphorescence measurement or the oxygen-pressure sensing. PtTFP-1 was coated on the surface of a delta wing model. The oxygen-pressure distribution on the coated model was successfully visualized in a cryogenic wind tunnel test. Copyright (C) 2008 John Wiley & Sons, Ltd.

In search of polymer backbones to bind organic radical pendant groups as redox centers for high-density charge storage application, polyether was employed as a flexible chain with a low glass transition temperature and affinity to electrolyte solutions. Cyclic ethers bearing nitroxide radicals were synthesized and polymerized via ring-opening polymerization utilizing various initiators. Polyethers bearing robust radical substituents such as 2,2,6,6-tetramethylpiperidin-l-oxyl-4-yl and 2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-l-oxyl-3-yl groups with high density, i.e., per repeating unit with small equivalent weights, were prepared by the anionic polymerization of the corresponding epoxides. Cyclic voltammetry of the radical polyethers, obtained for polymer/carbon composites confined at an aluminum current collector, revealed large redox capacities comparable to the formula weight-based theoretical values, which was ascribed to the efficient swelling and yet insoluble properties of the polyethers in electrolyte solutions by virtue of their high molecular weights and adhesive properties to be held on electrode surfaces. The redox capacity also indicated that the ionophoric polyether matrix accommodated electrolyte anions to compensate positive charges produced by the oxidation of the neutral radicals at the polymer/electrode interface, allowing charge propagation deep into the polymer layer by a site-hopping mechanism. Test cells fabricated with the polymer/carbon composite as the cathode and a Li anode, sandwiching an electrolyte layer, performed as a secondary battery at output voltages near 3.6 V without substantial degradation even after 100 charging-discharging cycles.

Possible structural aspects are discussed that justify the different resistance to reduction of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) both chemically (by reaction with ascorbic acid (ASC)) and electrochemically, in the presence of different polyelectrolytes Such as poly(sodium 4-styi-enesulfonate) (PSS), poly(sodium 4-styrenesulfonate-co-sodium maleate) at two different comonomer compositions (P(SS1-co-MA(1)) and P(SS3-co-MA(1))), and poly(sodium acrylate-co-sodium maleate) (P(AA1-co-MA(1))). Different dissociation constants are found for the complexes between TTC and the different polyelectrolytes by diafiltration (DIF). Related to this, spectroscopical differences are also found by H-1 NMR and UV-vis spectroscopies. Dynamic light scattering (DLS) showed a higher tendency to undergo intermolecular aggregation for P(SS1-co-MA(1)) in the presence of TTC, a result that could be related with a higher tendency for TTC to form hydrophobic ion pairs as a consequence of single stacking with the benzene sulfonate groups (BS) of this polyelectrolyte. On the other hand. the lower tendency for PSS to undergo intermolecular aggregation could be attributable to a higher probability to form more hydrophilic adducts by means of double stacking with TTC.

Poly[4,6-bis(dodecylthio)-1,3-phenylene-alt-2-methyl-1,3-phenylene] (Poly-S) was synthesized via Suzuki-Miyaura coupling of 1,3-dibromo-2,6-bis(dodecylthio)benzene and 2-methyl-1,3-phenylenebis(pinacol borate). After quantitative oxidation of the pendant sulfide moiety to the sulfoxide derivative (Poly-SO), the m-linked benzene rings were fused via intramolecular ring-closing condensation with excess triflic acid to form the corresponding poly(sulfonium cation) (Poly-S+) with a helical structure. Poly-S+ was quite soluble in non-polar solvents due to the long alkyl dodecyl chain. The Poly-S+ film, especially the film cast from its acetone solution, gave a polarized optical micrograph, suggesting an oriented structure of the helical poly(sulfonium) derivative. The X-ray diffraction pattern of the film supported a hexagonal columnar packing of the polymer. The polysulfonium derivative in the film state was converted to the corresponding poly(thiaheterohelicene) (Poly-TH) via the dealkylation with a basic potassium hydroxide methanol solution or pyridine. The Poly-TH film was doped with iodine. Its conductivity was enhanced about 30 times when compared to that of the undoped film. Copyright (C) 2008 John Wiley & Sons, Ltd.

The redox behavior of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) in the presence of different polyelectrolytes such as poly(sodium 4-styrenesulfonate) (PSS), poly(sodium 4-styrenesulfonate-co-sodium maleate) at two different comonomer compositions (P(SS1-co-MA(1)) and P(SS3-co-MA(1))), poly(sodium acrylate-co-sodium maleate) (P(AA(1)-co-MA(1))), and poly(sodium acrylate) (PAA) is studied. Due to aromatic-aromatic interactions, the polyelectrolytes containing benzene sulfonate groups produce a decrease on the reduction rate of TTC in the presence of ascorbic acid (ASC) and a shift of the anodic and cathodic peaks to higher negative potentials for the electrochemical reaction of TTC. As an important conclusion, these effects are a function of the linear aromatic density of the polyelectrolytes.

A non-volatile, bistable, and rewritable organic memory device was successfully fabricated with the layers of poly(2,2,6,6-tetramethylpiperidine-1-oxyl methacrylate) (PTMA) and poly(methyl methacrylate) (PMMA) containing silver salt. The PTMA layer was employed as a p-dopable material, while the silver salt-dispersed PMMA layer acted as an n-dopable material. The ON-OFF ratio between low-conductivity and high-conductivity states amounted to more than four orders of magnitude, and the retention time was longer than 10(3) sec. The device was characterized by excellent rewritability. Copyright (C) 2007 John Wiley & Sons, Ltd.

A luminescent porphyrin dye film has been coated onto a transparent separator on the cathode side of a direct methanol fuel cell (DMFC) to visualise clearly oxygen distribution under operating conditions by analysing emission from the dye.

An electrochromic (EC) cell using a viologen-based polymer as an EC material and a radical polymer bearing a redox-active 2,2,6,6-tetramethylpiperidin-N-oxyl (TEMPO) group per repeating unit as a counter electroactive material was fabricated. The radical polymer was spin-coated on an ITO/glass electrode as the counter electrode of the EC cell. The electrochromic material of the cell was a polyion complex consisted of poly(decyl viologen) and poly(styrene sulfonate) (PV 10-PSS), which was also spin-coated on the ITO/glass. An ion-conducting polymer gel Solution was sandwiched between the two electrodes. Electrochemical switching of the cell was monitored using the visible absorption of the PV 10-PSS complex (lambda(max) = 550 nm) that appeared in the reduced state, while the radical polymer was transparent in the visible region in both redox states. PV 10-PSS and the radical polymer were Concurrently reduced and oxidized, respectively, on each electrode during the charging process, which corresponded to the coloration of the cell. The decoloration of the polyion complex was effected by a discharging process under short circuit conditions. The electrochromic behavior of the cell was characterized by a remarkably low driving voltage, as a result of a small potential gap between PV 10-PSS and the radical polymer. The use of the organic redox polymers, not only for the low energy-driven electrochromic switching but also for the charge-storage purposes, allowed a universal design of a battery-like display device, with possible application to a flexible and totally organic electrochromic cell.

A dual-mode and a non-Stern - Volmer type oxygen pressure-sensitive coating was prepared by combining the cobaltporphyrin (CoP) ligated with a polymer and 1-pyrenebutyric acid (Py): the combination of the rapid and reversible oxygen (O-2)-adduct formation of the CoP was accompanied by a visible absorption spectral change and luminescence quenching of Py with oxygen. The oxygen sensor composed of CoP/Py was successfully characterized by a significantly high oxygen sensitivity under the practical atmospheric oxygen pressure of 10 - 21 kPa. Py was adsorbed on an anodized aluminium substrate. Its luminescence decreased by quenching with oxygen which obeyed the conventional Stern Volmer equation. Copolymers of vinylidenechloride with 1-vinylimidazole, 1-vinyl-2-methylimidazole, and 4-vinylpyridine (1, 2 and 3, respectively) were prepared to provide both an oxygen-barrier coating for the first luminescent Py layer and CoP ligation for tuning the oxygen-adduct formation equilibrium. The luminescent Py layer was further coated with a second polymer layer: The oxygen-barrier polymer coating enhanced the Stern - Volmer type luminescence intensity from the Py layer. Visible absorption of the CoP-containing polymer second layer increased in response to the oxygen-adduct formation or oxygen partial pressure, which overlapped and reduced the luminescence from the Py layer. The sum of the luminescence decreased along with an increase in the oxygen partial pressure, yielding a non-Stern - Volmer type response or high sensitivity to the oxygen partial pressure.

The electric conductivity of x-conjugated and radical-bearing polymers, i.e., polythiophenes bearing pendant galvinoxyl and phenoxyl radical groups, was measured using a microcomb-shaped electrode. The electric conductivity was found to be enhanced by the radical content in the polymer. The infrared (IR) and Raman spectroscopies suggested a structural change from an aromatic form to a quinoid one in the polythiophene backbone by the phenoxyl radical generation. The effect of the pendant galvinoxyl radical's unpaired electron on the electric conductivity of the polythiophene was discussed by comparing the conductivity of a radical-bearing polystyrene and a polythiophene mixed with low-molecular radical molecules. Copyright (C) 2007 John Wiley & Sons, Ltd.

The thiol group-terminated polythiophenes were prepared via the Pd-catalyzed coupling reaction of the bromo group-terminated polythiophene derivatives and methylthiophenylboronic acid, and were mixed with the nanometer-sized gold particle to form a self-assembled network film of the alternate conjugation of the polythiophene with the gold nanoparticle. The electron microscopy and X-ray photoelectron spectroscopy of the films supported the formation of a polythiophene/gold nanoparticle alternate network structure through the S-Au linkages. The high electric conductivity and its low activation energy on the network film suggested that the conductive characteristic of the film originated from that of the pi-conjugated polythiophene backbone connected with the gold nanoparticle. (c) 2007 Elsevier Ltd. All rights reserved.

Structures and electrochemical behaviors of nitroxide radicals reveal that their rapid and reversible redox reactions are based not only on their chemical stability but also on the increased sp(2) character of nitrogens which is intermediate between the purely sp(2) and sp(3) nitrogens in oxoammonium cations and amines, respectively.

A series of highly acid-functionalized poly(phenylene oxide)s and poly(phenylene sulfone) were prepared and proton conductivity in their membranes is discussed. Phosphorylated poly(phenylene oxide)s were prepared via the oxidative polymerization of phosphonoxyphenols in alkaline water, along with a facile monomer preparation. A poly(phenylene oxide) bearing a sulfamide acid group was prepared by reacting amidosulfate with the corresponding carboxylated poly(phenylene oxide). A sulfonated poly(phenylene sulfone) was prepared by hydrogen peroxide oxidation of the sulfonated poly(phenylene sulfide). All these acid-functionalized polymers showed appropriate thermal stability based on the aromatic backbone. The polymers had a high ion-exchange capacity, were water-soiuble, but gave transparent and flexible membranes after compositing with the poly(ethylene oxide). Some of the membranes displayed a high proton conductivity of 10(-4) S cm(-1) at 120 degrees C under dry conditions.

Self-assembled porphyrins via noncovalent bonding have attracted wide-ranging researchers in material science. We reported herein the synthesis of the tetraphenyl porphyrin derivatives bearing uracyl groups as acceptor-donor-acceptor (ADA) type hydrogen bonding units, through the condensation of 5,10- or 5,15-bis (3-amino-4-ethylhexylphenyl) porphyrin derivatives with 6-carboxyuracyl derivatives. When two porphyrins having uracyl groups at the different substituted positions were respectively mixed with a melamine derivative in benzene, H-1 NMR spectra showed that the 5,15 substituted uracyl porphyrin formed a hydrogen-bonded suprastructure with the melamine derivative as a complementary molecule to the uracyl moiety, although the other 5,10-substituted uracylporphyrin could not form such a structure. The SEM observation indicated that the mixture with the 5,15-substituted uracyl porphyrin and the melamine with long alkyl chains formed a sheet-like structure. Copyright (C) 2007 John Wiley & Sons, Ltd.

N,N-Bis(4-methoxyphenyl)-4-(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolin-2-yl)phenylamine (1) was synthesized as a durable nitronyl nitroxide radical combined with a triarylamine moiety. Cyclic voltammetry and UV-Vis absorption spectra during the electrochemical oxidation of 1 revealed that the first redox was derived from the triarylamine moiety. The ionization potential of I was measured by photoelectron spectroscopy to be -5.4 eV, which was appropriate as a hole-transporting material. A single-layer hole-only device was fabricated with the radical molecule 1 dispersed in polycarbonate (ITO/1:polycarbonate/Al): The radical-layer exhibited a maximum current density of 0.2 mA/cm(2) which was applicable for organic electronic devices. (c) 2006 Elsevier Ltd. All rights reserved.

Aromatic-aromatic interactions are found between the cationic molecule 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and the molecule poly(sodium 4-styrenesulfonate) (PSS) which makes the overall interaction of TTC with PSS more intense than the interaction with other polyanions containing sulfonate groups and produces a decrease on the redox ability of TTC. Diafiltration was used to compare the binding of TTC to PSS, poly(sodium vinylsulfonate) (PVS), and the more hydrophobic poly(sodium 2-(N-acrylamido)-2-methyl-propanesulfonate) (PAMPS). The UV-vis spectrum of TTC is changed in the presence of the aromatic polyanion. The H-1 NMR signals of TTC are broadened and shifted in the presence of PSS, suggesting the occurrence of pi-pi interactions. Moreover, nuclear Overhauser effects (NOE) between the TTC and PSS protons are found. Possible structures for the complex are proposed.

Three polystyrenes bearing redox-active nitroxide radical(s) in each repeating unit, poly[4-(N-tert-butyl-N-oxylamino)styrene] (1), poly[3,5-di(N-tert-butyl-N-oxylamino)styrene] (2), and poly[4-(N-tert-butyl-N-oxylamino)-3-trifluoromethylstyrene] (3), were synthesized via free radical polymerization of protected precursor styrenic derivatives and subsequent chemical oxidation. The radicals in these polymers were robust at ambient conditions, and the polymers possessed radical densities of 2.97 x 10(21), 4.27 x 10(21), and 1.82 x 10(21) unpaired electrons/g for 1-3, respectively, resulting in an electrode-active material with a high charge/discharge capacity. Particularly, the dinitroxide functional polymer 2 possessed the highest radical density. Cyclic voltammetry of the poly(nitroxylstyrene) 1 revealed a reversible redox at 0.74 V vs Ag/AgCl, which was assigned to the oxidation of the nitroxide radical to form the oxoammonium cation (p-type doped state). On the other hand, the poly(nitroxylstyrene) ortho-substituted with the electron-withdrawing trifluoromethyl group 3 showed a reversible redox at -0.76 V, ascribed to the n-type redox pair between the nitroxide radical and the aminoxy anion. Thus, the nitroxide radical polymer could be switched from p-type material suitable for a cathode to n-type material (anode-active) via altering the electron-withdrawing character of the substituents on the poly(nitroxylstyrene). This is the first report of an n-type radical polymer and the first report of using substituent effects to switch the redox behavior of the polymer. This versatile switching ability enables these polymers to function as components of metal-free electrodes in rechargeable batteries.

A magnetically active, purely organic dot array was formed by the selective deposition of polyradical nanoparticles on array-like-formed pits on a silicon substrate. The nanometer-sized polyradical particles, poly(4-methacryoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), were prepared by the emulsion polymerization of 4-methacryloy-loxy-2,2,6,6-tetramethylpiperidine-1-acetoxyl followed by a deprotection reaction and oxidation in air. The size (diameter) and radical spin concentration of the polyradical nanoparticles were tunable between the polymerization and oxidation conditions. Electrochemical studies revealed the redox property of the polyradical nanoparticles. The magnetic response image of the polyradical nanoparticles was obtained by magnetic force microscopy, reflecting their radical spin concentrations. These results suggested a possible approach for the use of organic polyradical nanoparticles as organic magnetic dot arrays. (c) 2006 Wiley Periodicals, Inc.

Poly [2-{bis(4-methoxyphenyl)amino}phenyl-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] 1 was prepared via the Gilch reaction of the p-bis(chloromethyl)benzene monomer, 2-{bis(4-methoxyphenyl)aminophenyl)-alpha,alpha'-dichloro-p-xylene. The Gilch reaction facilitated the preparation of the polyphenylenevinylene with a triarylamine pendant group when compared to that via the Heck polycondensation. The molecular weight of the polymer was approximately 4.0 x 10(5), and it was soluble in common solvents and was reversibly redoxed due to the pendant arylamine moiety. Chemical oxidation of I afforded the corresponding aminium polyradical 1(+) with the half life-time of ca. 2 weeks under ambient conditions. ESR and magnetization measurements of 1(+) revealed a forbidden multiplet signal and an average spin quantum number (S) of 3/2 at low temperature, respectively. The polyradical 1(+) was the first example of a high molecular weight, high-spin organic polymer with solvent-solubility and film formability. 2,3-Bis[N,N-bis(4-methoxyphenyl)aminophenyl]stilbene 2 and its aminium diradical 2(+) were also prepared as the model dimer compounds; 2(+) was a triplet molecule at low temperature. The effect of the pi-conjugated poly(1,4-phenylenevinylene) backbone on the high-spin alignment was also discussed.

The interaction of the pharmacologically important chlorpheniramine maleate (CPM) with polyanions containing sulfonate groups such as poly(sodium 4-styrenesulfonate) (PSS), poly(sodium vinylsulfonate) (PVS), and the more hydrophobic poly(sodium 2-(N-acrylamido)-2-methyl-propanesulfonate) (PAMPS) has been studied by H-1 NMR. It was found that the pK(a) of the low-molecular weight molecule (LMWM) may be modified by its interaction with the polyanions, changing from 3 to 5, due to electric charge compensation. Interestingly, the interaction of CPM with PSS produces changes in CPM resonances, such as a general broadening and upfield shifts of the signals, and NOE effects between the LMWM and the water-soluble polymer (WSP) that indicate the presence of pi-pi interactions. (c) 2006 Elsevier Ltd. All rights reserved.

We have synthesized a 5,15 meso-substituted methyluracyl porphyrin derivative bearing 6-methyluracyl units directly at the meso positions. The atropisomerization was regulated by steric replusion between the methyl substituents. When the atropisomers were mixed with alkylated melamine as a complementary hydrogen-bonding unit, the hydrogen-bonded assemblies were analyzed by diffusion-ordered spectroscopy (DOSY) in solution, which clarified that the alpha alpha isomer formed a face-to-face dimer, whereas the alpha beta isomer took a zigzag structure.

Electroactive and transparent organic radical polymers offered a novel design of materials for electrochromic (EC) devices. A radical polymer containing 2,2,6,6-tetramethylpiperidinoxyl (TEMPO) groups as redox active sites per repeating unit was spin-coated on a counter ITO/glass electrode of the EC device which was also comprised of Prussian blue (PB) as an electrochromic material on ITO and ion-conducting polymer gel between the two electrodes. Electrochemical switching of the cell was monitored using the visible absorption of PB (lambda(max) = 700 nm) that appeared in the oxidized (mixed-valence) state, while the radical polymer was transparent in the visible region in both redox states. PB and the radical polymer were concurrently reduced and oxidized, respectively, on each electrode during the charging process, which corresponded to the decoloration of the cell. The coloration was effected by a discharging process. The electrochromic switching and stability of the cell was characterized by a low driving voltage AV and, consequently, a small driving energy integral Delta Vi(t)dt, as a result of a small potential gap between PB and the radical polymer. The optical switch was fast and fully reversible by virtue of the large heterogeneous electron transfer rate constant of the TEMPO center (k(0) approximate to 10(-1) cm/s). The polymeric counter electrode material, without dissolution into the electrolyte layer, led to a good open circuit memory that did not require refreshing charges to maintain the redox states of PB.

A nitroxide radical functional polymer was photocrosslinked for the first time without significant side reactions, producing a cathode-active thin film, leading to an organic-based paper battery.

A durable nitroxide radical combined with a triarylamine moiety exhibited a hole-drift mobility of 6 x 10(-3) cm(2) V-1 s(-1), to which the aminophenyl nitroxide structure contributed.

A layer-by-layer assembled and molecular-complexed polymer membrane was prepared by the simple combination of poly(4-styrenesulfonic acid) and poly(allylamine) on a comb-shaped gold electrode: it displayed a very high proton conductivity of 10(-3) S cm(-1) under a dry condition at 120 degrees C.

Magnetic force microscopy (MFM) was used to study the single-molecular magnetic response of the proxyl radical-terminated poly (amidoamine) dendrimer. Local magnetization of the organic radical molecules was evaluated by the MFM intensity, which correlated to the number of unpaired electrons per molecule.

A H-1 NMR study is presented for the binding of rhodamine B (RB) to the polyanion containing aromatic groups poly( sodium 4-styrenesulfonate) (PSS), which is also evidenced by diafiltration. H-1 NMR spectra showed an accentuated upfield shift of proton H6 ' of the benzoic ring of RB at pH 7, indicating the stacking of RB onto PSS. The corresponding structure is proposed which is in accordance to Hunter and Sanders rules. At pH 2, an upfield shift of the xanthene protons of RB would indicate a highly condensed state for this molecule.

Simply stirring 2,6-dimethylphenol with a small amount of copper complex catalyst in alkaline water provided a green way to prepare poly(2 6-dimethyl-1.4-phenylene oxide) in water. We have searched for the optimum alkaline-resistant metal catalyst from a series of watersoluble copper complexes. The formed polymer was easily separated as an off-white powder by filtration after salting out. (c) 2006 Elsevier Ltd. All rights reserved.

A high-spin polyradical, poly {[4-(dianisylaminium)phenyl]acetylene} 1(+), was synthesized as a pi-conjugated polymer with an excess of the one-handed helical structure bearing stable aminium cation radicals. [4-(Dianisylamino)phenyl]acetylene (3) was synthesized and polymerized using [Rh(norbornadiene)Cl](2) in (R)-1-phenylethylamine, (S)-1-phenylethylamine, or triethylamine to produce the corresponding poly {[4-(dianisylamino) phenyl]acetylene} 1 (1((R)-PEA), 1((S)-PEA), and 1(TEA)). The positive and negative Cotton effects were observed at 270-450 nm for the polymers 1((R)-PEA) and 1((S)-PEA), indicating that an excess of the one-handed helical polyacetylene backbone was induced by the polymerization using chiral solvents despite the achiral monomer. The oxidation of 1 with NOPF6 gave the corresponding aminium polyradicals 1(+), and the circular dichroism (CD) spectrum was observed even after the oxidation of the helical polyradical 1((R)-PEA)(+). The SQUID and NMR shift measurements indicated a high-spin state of the polyradical at room temperature and a contribution of the well-regulated helical structure to the through-space interaction between the aminium cation radicals.

The stability of quadruple hydrogen bonding in the cyclic tetramer of a metallo-porphyrin before and after a covalent fixation was investigated. According to competition and energy-transfer experiments, the exchange reaction between the cyclic tetramers of the metallo-porphyrin was fully suppressed by the covalent fixation. This spontaneous cyclization-covalent fixation strategy based on olefin metathesis can open the way to the use of cyclic assemblies in a solid phase.

A membrane with an oxygen-binding capability and nanometer thickness was prepared by complexing cobalt-phthalocyanine as an oxygen carrier with the copolymer of vinylimidazole and octyl methacrylate. The complex showed reversible oxygen-binding in the solution state at low temperature. The permeability coefficient of oxygen (P-O2) through this membrane was much higher than that of nitrogen (P-N2) (P-O2/P-N2 > 20) and increased at lower upstream oxygen pressure. The facilitation of oxygen transport was augmented by increasing the concentration of the oxygen carrier, cobalt-phthalocyanine fixed in the membrane. (C) 2005 Elsevier B.V. All rights reserved.

The pore surface of a porous glass membrane was modified with phthalocyanato- and tetraphenylporphyrinato-1-(benzylimidazole)cobalt(II) complexes, which specifically and reversibly binds molecular oxygen from air. The lower oxygen-binding affinity enhanced surface oxygen diffusion which improved permeability (3.0 x 10(-11) kmol ms(-1) m(-2) kPa(-1)) and (oxygen/nitrogen) permselectivity (10).

N-(4-vinyl)benzylimidazole and its copolymer with octyl methacrylate (PBIOM) were synthesized and characterized, and oxygen-binding properties of cobaltporphyrin (CoP) complexes with imdazole ligands were studied. The weight-average molecular weight and imidazole content of PBIOM were determined to be 3.4 x 10(5) and 57 mol % by GPC and elemental analysis, respectively. PBIOM or benzylimidazole (BIm) and CoPn chloroform solution were mixed to complex the imidazolyl residue of the ligands with the fifth coordination site of CoP under nitrogen atmosphere to get Cop complexes. CoP complex displayed a reversible change in the UV-visible absorption spectrum from the deoxy form to the oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-binding equilibrium curves of CoP complexes obeyed a Langmuir isotherm, to give the oxygen-binding affinity p(50) (oxygen partial pressure at which half of the CoP binds with oxygen). At the same partial oxygen pressure, the oxygen-binding ratio of CoP-BIm complex was a little larger than that of CoP-PBIOM complex. The oxygen-binding affinity of CoP-PBIOM complex in the solid membrane state was larger than that in chloroform solution. The half lifetime of CoP-PBIOM membrane at 60 degrees C was 40.7 h,while that of CoP-Blm membrane (poly(octyl methacrylate) as matrix) was 8.8 h, indicating that polymer ligand significantly prolonged the lifetime of CoP complex.

2,5-Bis(chloromethyl)triphenylamine I was prepared and polymerized via the Gilch reaction to give poly(2-diphenylamino-1,4-phenylenevinylene) 2G as a solvent-soluble Phi-conjugated polymer. 1 was also polymerized via the chemical vapor deposition to yield the precursor polymer of 2C, which was heated under vacuum to yield a yellow or brown thin film of 2C on substrates such as glass and a silicon wafer. Spectroscopies of the film supported the formation of the poly (2-diphenylamino-1,4-phenylenevinylene) 2C. The arylamine moiety of the 2C film worked as a functional group like a redox site. (c) 2006 NIMS and Elsevier Ltd. All rights reserved.

The packing of submicrometer-sized polystyrene particles within the micrometer-sized recessed patterns were achieved using silicon-microfabricated substrates and a simple dipping and pulling-up process. The polystyrene particles were selectively deposited within the micrometer-sized square, triangular, or circular recessed patterns by tuning the experimental conditions during the pulling-up process. The process produced a capillary force, i.e., a gas-liquid interfacial tension, to push the particles into the recessed patterns on the substrate. In most cases, the selectively depositing particles within the recessed patterns self-organically formed the closest packing structures. However, a special phenomenon, cubic packing structures of the particles, was observed when using square patterns with a few times larger side-length than the particle diameters. Several particle packing structures within different-sized square patterns were demonstrated, and the relationship between the particle packing structures and square pattern sizes were discussed. (c) 2006 NIMS and Elsevier Ltd. All rights reserved.

Hyperbranched poly [(4-methoxyphenyl-N-yloammonio)-1,2(or 4)-phenylenevinylene-1,2(or 4)-phenylene], obtained by the polycondensation of N-(4-methoxyphenyl)-N-(4-vinylphenyl)-3-bromo-4-vinylaniline and the subsequent oxidation, three-directionally satisfied the non-Kekule-type pi-conjugation and ferromagnetic connectivity of the unpaired electrons of triarylammoniumyl cationic radicals, and behaved as a high-spin organic polymer even at room temperature. The trimer model compound, N- (4-{5- [N,N-bis(4-methoxyphenyl) amino] - 2-methylstyryl}-3-methylphenyl) -N(4-15-[N,N-bis(4-methoxyphenyl)amino]-2-methylstyryl)phenyl)-4-methoxyaniline, was synthesized from N-(4-methoxyphenyl)-N-(4-vinylphenyl)-3-methyl-4-vinylaniline. The corresponding ammoniumyl triradical displayed an average S (spin quantum number) value of 3/2, which supported the strong spin-coupling between the unpaired electrons of the ammoniumyl radicals through the pi-conjugated and branched phenylenevinylene structure. Head-to-tail linkage and the branched structure of the polymer were also studied by a model reaction of N-(4-methoxyphenyl)-N-(4-vinylphenyl)3 - methyl-4-vinylaniline and bromobenzene.

This paper describes the selective formation of a cyclic tetramer from a readily synthesized metalloporphyrin with two self-complementary quadruple hydrogen-bonding units. The extremely strong quadruple hydrogen-bonding unit, 2-ureido-4[1H]-pyrimidinone, enabled the formation of a stable cyclic tetramer based on a tetraphenylporphyrin derivative over a wide concentration range. This hydrogen-bonded tetramer is a new functional unit for use in a higher-ordered architecture of a supramolecular porphyrin assembly.

A new triradical molecule, 2,6,10-tris(dianisylaminium)-3,7,11-tris(hexyloxy)triphenyiene 1(3+), was synthesized by oxidative trimerization, palladium-catalyzed amination, and subsequent oxidation. It was chemically stable with a half-life > 1 month and displayed the magnetic parameter of S = 3/2 even at room temperature.

Experimental Raman and infrared spectra of poly(p-phenylenevinylene) have been analyzed on the basis of the normal coordinate calculations based on the density functional theory method at the B3LYP/cc-pVDZ level for a model oligomer. Vibrational modes corresponding to optically active modes of an infinite polymer chain have been selected from the calculated results. On the basis of these normal vibrations, the observed vibrational spectra of poly( p-phenylenevinylene) have been explained successfully. The angles between the calculated transition dipole moment vectors and the polymer axis for some infrared bands agree with those derived from observed infrared dichroic spectrum. (c) 2005 Elsevier B.V. All rights reserved.

The water-insoluble, thermostable and homogeneous polymer complex membrane formation of polysulfonic acids was examined by modifying the preparation conditions of the layer-by-layer adsorption method of the acid and base polymers. The complexation Of poly(4-styrenesulfonic acid) in the 0.15 unit mM solution with poly(allylamine) gave a polymer complex membrane on a gold substrate in which one polymer layer was formed with a thickness of 1 nm. Properties including the proton conductivity of the membrane suggested possible applications of the polymer complex membrane.

Nitroxide-substituted polyether was synthesized as a cathode-active material for a secondary battery. Anionic ring-opening polymerization of a TEMPO-bearing glycidyl ether was carried out under bulk conditions to yield the corresponding polymer with the molecular weight of > 10(4). The obtained polymer was insoluble, but slightly swollen in the electrolyte solution (ethylene carbonate/propylene carbonate). The test cell fabricated with a carbon composite cathode of this radical polymer displayed a plateau voltage at 3.5 V vs. Li/Li+. The cell performance was maintained even with a higher amount of the radical polymer loaded in the composite electrode, which could be ascribed to the flexible and rubbery polyether backbone and its higher compatibility with the electrolyte solution.

Poly[1,2,(4)-phenylenevinyleneanisylaminium] 1 was synthesized by one-pot palladium-catalyzed polycondensation of N-(3-bromo-4-vinylphenyl)-N-(4-methoxyphenyl)-N-(4-vinylphenyl)amine 3 and subsequent oxidation with the thianthrene cation radical tetrafluoroborate: compound 1 three-directionally satisfies a non-Kekule-type pi-conjugation and the ferromagnetic connectivity of the unpaired electrons of the triarylaminium cationic radical. The average molecular weight of the polymer was 4700-5900 (degree of polymerization = 11-14), which gave a single molecular-based and globular-shaped image of ca. 15 nm diameter by atomic and magnetic force microscopies under ambient conditions. The aminium polyradical 1 with a spin concentration (determined by iodometry) of 0.65 spin/unit displayed an average S (spin quantum number) value of (7)/(2) even at 70 degrees C according to NMR and magnetization measurements.

An N-phenylcarbazole-containing poly(p-phenylenevinylene) (PPV), poly [(2-(4'-carbazol-9-yl-phenyl)-5-octyloxy-1,4-phenylenevinylene)-alt-(2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene)] (Cz-PPV), was synthesized, and its optical, electrochemical, and electroluminescent properties were studied. The molecular structures of the key intermediates, the carbazole-containing boronic ester and the dialdehyde monomer, were crystallographically characterized. The polymer was soluble in common organic solvents and exhibited good thermal stability with a 5% weight loss at temperatures above 420 degrees C in nitrogen. A cyclic voltammogram showed the oxidation peak potentials of both the pendant carbazole group and the PPV main chain, indicating that the hole-injection ability of the polymer would be improved by the introduction of the carbazole-functional group. A single-layer light-emitting diode (LED) with a simple configuration of indium tin oxide (ITO)/Cz-PPV (80 nm)/Ca/Al exhibited a bright yellow emission with a brightness of 1560 cd/m(2) at a bias of 11 V and a current density of 565 mA/cm(2). A double-layer LED device with the configuration of ITO/poly(3,4-ethylenedioxy-2,5-thiophene):poly (styrenesulfonic acid) (60 nm)/Cz-PPV (80 nm)/Ca/Al gave a low turn-on voltage at 3 V and a maximum brightness of 6600 cd/m(2) at a bias of 8 V The maximum electroluminescent efficiency corresponding to the double-layer device was 1.15 cd/A, 0.42 lm/w, and 0.5%. The desired electroluminescence results demonstrated that the incorporation of hole-transporting functional groups into the PPVs was effective for enhancing the electroluminescent performance. (c) 2005 Wiley Periodicals, Inc.

A purely organic and high-spin polyradical molecule was synthesized, along the non-Kekule and non-disjoint design of the pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4,6-substituted with the robust arylamininium radicals. 4,6-Bis(bis(4-methoxyphenyl)amino)-2-bromostyrene was synthesized and polymerized with a Pd-phosphine catalyst to afford the head-to-tail linked polyradical precursor. Oxidation of the polymer with SbCl5 gave the aminium polyradical with a half-fire of >10 days at room temperature. A high-spin ground state with in average S = 5/2 for this polyradical was proved by magnetic susceptibility and ESR. (c) 2005 Elsevier Ltd. All rights reserved.

Poly(phenylene oxide)s bearing carboxylic and sulfonic acids were prepared via oxidative polymerization of the corresponding phenol derivatives. Polymerization of 2-(ethoxycarbonyl)6-methylphenol yielded poly [2-(ethoxycarbonyl)-6-methyl- 1,4-phenylene oxide] with a high molecular weight, and its hydrolysis produced poly(2-carboxy-6-methyl-1,4-phenylene oxide) with a series of carboxylic acid contents. Polymerization of 4-bromo-2-(ethoxysulfonyl)-6-methylphenol produced poly(2-methyl-6-sulfo-1,4-phenylene oxide). The acid-functionalized poly(1,4-phenylene oxide)s showed a high thermal stability and proton conductivity.

Helical polymers and macromolecules have precisely ordered stereostructures, and their potential applications include chiral separation and sensing based on molecular recognition and liquid crystalline formation by molecular ordering. Among them, pi-conjugated polymers with a helical structure have often exhibited unique electro- and magneto-responsibilies. In this review, we describe the helical pi-conjugated macromolecules as electro- and magneto-responsible materials including our recent studies. In Chapter 2, the recent studies of helical polymeric molecules with pi-conjugated structures are reviewed. We focus on "helicene" derivatives, which consist of fused-benzene and/or thiophene rings, in Chapter 3 and summarize their syntheses, characteristics, and optical properties based on the stiff structures and molecular ordering. Helical ladder polymers, "poly(thiaheterohelicene)s" comprised of fused-benzothiophene rings, are discussed in Chapter 4 among their stiff helical structure and pi-conjugation. The combined functions of electro- and magneto-properties of the chiral polymer are described using the example of poly(thiaheterohelicene)s, such as electron transmission along the helical main-chain and a molecule model of a molecular solenoid, in the final section.

A calix[4]arene-porphyrin duplex was prepared by mixing equimolar amounts of hydroxy or carboxy calix[4]arene derivatives and pyridyl or o-aminophenylporphyrin derivatives. Electrospray ionization mass spectrometry (ESI-MS) was applied to screen a suitable pair of a calix[4]arene and a porphyrin. meso-Tetra(2-pyridyl)porphyrin formed a duplex with tetrahydroxy or tetrahydroxymethylcalix[4]arene via triple or quadruple hydrogen bonds. H-1 NMR spectra showed that the tetrahydroxycalix[4]arene was symmetrically located upon the porphyrin ring, whereas trihydroxycalix[4]arene was slanted on the porphyrin ring. The duplex of meso-tetra(2-pyridyl)porphyrinatocobalt(II) and tetrahydroxymethylcalix[4]arene formed a complex with benzylimidazole, which was capable of reversible dioxygen-binding. The capping structure upon porphyrin provided by calix[4]arene raised the life-time of dioxygen-adduct compared with the porphyrin without calix[4]arene.

The oxidative polymerization of sulfonatopropoxyphenols in alkaline water, along with the easy monomer preparation, provided a simple and atom economical way to prepare sulfoalkoxy-pendant poly(phenylene oxide)s. The polymerization in alkaline water reduced the oxidation potential of the sulfonated phenols, and produced water-soluble polymers. The polymers produced a transparent, tough, and flexible membrane, which showed high thermal stability and proton conductivity.

Synthesis and characteristics of poly(3,4-azopyridylene) (PAP), conductivity and oxygen-binding affinity of its complex with meso-alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl) porphyrinatocobalt(II) (CoP) were studied. PAP was prepared by oxidative polymerization of 3,4-diaminopyridine (DAP) in DMF solution using CuCl/pyridine as the catalyst. IR and NMR results showed that the peak of amido group in DAP was converted to the azo group in PAP and a pi conjugated polymer was synthesized. The average molecular weight of PAP was determined to be 5.0 x 10(3). The PAP-CoP complex was prepared by complexing the pyridyl group of PAP with the fifth coordination site of CoP in DMF solution. In comparison with the CoP complex with a non-pi conjugated polymer, the PAP-CoP complex shows good electroconductivity of 5.8 x 10(-6) S cm(-1). The PAP-CoP complex displays a reversible change in the UV-Visible absorption spectrum from the deoxy form to the oxy or oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-response behavior was monitored at the absorbance ascribed to the oxy form at 548 nm to give the oxygen-binding affinity. The oxygen-binding equilibrium curves of PAP-CoP complex obey a Langmuir isotherm. DMF has great effects on the oxygen-binding properties of the PAP-CoP complex. The oxygen-binding affinity of PAP-CoP complex in the solid state is higher than that in DMF solution. With decreasing temperature, the oxygen-binding affinity of the PAP-CoP complex increases.

The dissolution and diffusion processes of oxygen in and through poly ( octyl methacrylate-co-vinylimidazole) (OIm)/cobaltporphyrin complexed membranes were discussed. Facilitated oxygen transport through a polymer membrane containing meso-alpha, alpha, alpha, alpha-tetrakis (o-pivalamidophenyl) porphyrinatocobalt ( Cop) as a fixed oxygen carrier was analyzed by a dual-mode transport model. It was found that CoP fixed in the solid membrane rapidly and reversibly bound with oxygen and the oxygen-binding equilibrium constants of CoP ( K) was 14 mol(-1)L. The oxygen absorption for the CoP-OIm membrane obeyed a Langmuir-type isotherm, while the nitrogen absorption showed a proportional increase with nitrogen pressure according to Henry's law. The physical solubility coefficient of oxygen (k(D)) in the polymer matrix was calculated to be 4.4 x 10(-5) cm(3) (STP) cm(-3) Pa-1 according to the adsorption results. Oxygen permeability coefficients (Po-2) of the OIm-CoP membranes steeply increased with a decrease in the pressure difference (Po-2) while Po-2 for the control membrane composed of inactive ( oxidized) Co(III) P was small and independent of po(2) indicating that the CoP carrier fixed in the membrane, interacts with oxygen and facilitates oxygen transport. The facilitation factor ( G) that indicates the degree of facilitated transport was 9. The ratio of the diffusion coefficient of oxygen for hopping between the fixed carriers (D-C) to the physical diffusion coefficient of oxygen through the matric polymer (D-D) was 0.08.

Two poly(p-phenylenevinylene) derivatives, TPA-PPV and TPA-CN-PPV, bearing a triarylamine pendant were synthesized by the Wittig-Horner and Knoevenagel reactions, respectively. The optical properties of the polymers were improved by energy transfer from the triarylamine pendant to the poly(p-phenylenevinylene) main chain. Cyclic voltammetry revealed that the HOMO energy level of the pendant TPA moiety is higher than that of the PPV main chain, suggesting that the hole injection from ITO into the TPA moiety, then from the TPA moiety into PPV is more favorable than directly from ITO into the PPV main chain. A single-layer light-emitting diode using TPA-PPV as the emitting layer exhibited a maximum brightness of 790 cd/m(2) at a bias of 8 V, while the control device employing commercially available MEH-PPV as the emitter showed a maximum brightness of 250 cd/m(2) under 11 V. The higher brightness combined with the higher current density was attributed to the effective hole injection and/or hole transport in the TPA-PPV-based device. © 2005 Elsevier Ltd. All rights reserved.

Synthetic iron(II) porphyrin (FeP) is equivalently incorporated into recombinant Thermotoga maritima xylanase B (TMX; family F/10 of glycoside hydrolase), producing a heat-resistant artificial hemoprotein (TMX-FeP) that can bind and release oxygen (O-2) in aqueous medium (pH 7.3, 25 ° C) in the same manner as hemoglobin and myoglobin. The oxygenated species was sufficiently stable; the half-lifetime against the ferric state (τ(1/2)) was 5 h. This O-2-carrying hemoprotein showed a high degree of thermal stability over a wide range of temperatures up to 90 ° C (τ(1/2) = 5 min at 90 ° C and 9 min at 75 ° C). Dictyoglomus thermophilum xylanase B (DTX; family G/11) also incorporates FeP, and DTX-FeP showed identical O-2-binding parameters and thermostability. TMX-FeP is capable of catalyzing the β-1,4-D-xylan hydrolysis reaction. Its larger K-m value compared to that of TMX itself suggested competitive FeP binding to the active site of the host enzyme.

A novel helical aromatic polymer comprised of fused benzothiophene rings, poly(thiaheterohelicene), was synthesized via an intramolecular ring-closing reaction with a controlled helicity to one-sided bias. The synthetic helicity control involved the induction of the helical conformation and its fixation. The ladder polymer showed both an extended pi-conjugation and planarity and a very stiff helical structure.

A membrane of a cobalt tetraazaporphyrin polymer complex was prepared with a nanometer thickness and used as an oxygen-facilitated transport membrane. Rapid and reversible oxygen binding to the cobalt tetraazaporphyrin complex with a polymeric imidazole ligand was observed at low temperature. Oxygen transport through the membrane was facilitated and a high (oxygen/nitrogen) permselectivity of 28 was obtained.

An artificial gill has been developed that transfers oxygen from water to air, using oxo-molybdenum(IV)5,10,15,20-tetramesitylporphyrin ((MoO)-O-IV(tmp)) dissolved in o-xylene as an oxygen carrier solution and the energy of visible light. The oxygen partial pressure in the oxygen carrier solution is changed by photo-irradiation to enhance both the oxygen uptake from water and the oxygen release to air. The ratio of the oxygen mass transfer coefficient of the oxygen carrier solution to that of water is 0.746 for oxygen uptake and 0.654 for oxygen release. In designing a large-scale artificial gill for supplying oxygen to a closed space underwater such as submerged vessel, the required membrane surface area, the seawater flow rate and the reservoir tank volume were 123 m(2), 0.00533 m(3) s(-1), and 5.06 m(3), respectively. These values increased as the oxygen partial pressure of seawater decreased. However, the high partial pressure of oxygen required for human respiration (20.0 kPa) can be provided in a closed space even from seawater with an oxygen partial pressure as low as 10.0 kPa. This newly developed artificial gill may be useful for deep sea activities, such as underwater exploration, marine research and underwater habitation. (C) 2004 Elsevier B.V. All rights reserved.

Poly(3-chiral methylsulfinyl-1,2-phenyleneoxide) was synthesized, and the regioselective intramolecular ring-closing of the pendant sulfoxide on the polymer formed the corresponding helical ladder structure comprising of a fused phenoxathiine ring. The CD of the ladder polymer gave a Cotton effect which was caused by the chirality of the pendant group.

A series of triphenylmethanes terminated with (a) hydrogalvinoxyl(s), bis(4-tert-butylphenyl)-(4-hydrogalvinoxylphenyl)methoxymethane lad, tris(4-hydrogalvinoxylphenyl)methoxymethane 2ad, and tris{4-[bis(4-hydrogalvinoxylphenyl)methoxymethyl]phenyl}methoxymethane 3ad, were prepared and oxidized to the corresponding galvinoxyl radicals, 1af, 2af, and 3af, which have one, three, and six galvinoxyl radical(s), respectively. Chemical reduction of the galvinoxyl radicals with a Na/K alloy gave stable intermediates, i.e., the tetraanion, decaanion, and docosaanion. The tetraanion was oxidized with an equimolar amount of iodine at ca. 170 K to the galvinoxyl radical-combined triphenylmethyl radical 1cf The ESR signal of the biradical at room temperature indicated an exchange interaction between the two radicals. The spectrum at 140 K had a zero-field splitting and Delta M-S = +/- 2 transition signal at half-field, which are characteristic of a multiplet species.

Poly[bis(4-methoxyphenyl)aminiumacetylene]s 1(+) were designed and synthesized as a pi-conjugated polymer bearing multiple aminium radicals. Bis(4-methoxyphenyl)aminoacetylene and 1-methyl-2-bis(4-methoxyphenyl)aminoacetylene were synthesized and polymerized with a metathesis catalyst to yield poly [bis(4-methoxyphenyl)aminoacetylene] 1a and poly[1-methyl-2-bis(4-methoxyphenyl)aminoacetylene] 1b, respectively. The oxidation of 1 with SbCl5 gave the corresponding aminium polyradicals 1(+). The introduction of a methyl group onto the polyacetylene backbone in 1b(+) significantly enhanced the chemical stability or life-time of the poly(aminium radical). The high-spin ground state with an average S (spin quantum number) = 4/2 for 1b(+) was proven by magnetic susceptibility, magnetization, and ESR measurements.

A helical ladder polymer composed of a fused-benzothiophenium ring was synthesized via the intramolecular ring-closing reaction of the methylsulfoxide-substituted poly(1,3-phenylene). The precursor polymer was prepared by the palladium-catalyzed polymerization of 1,3-dibromobenzene and 1,3-phenylenebisborate and the following quantitative oxidation. The intramolecular ring-closing of the precursor polymer yielded poly [phenylene-4,6-bis(methylsulfonio)- 1,3-diyl triflate]. The polymer structure did not involve any structural defects based on NMR analysis, which was supported by the model dimers and the control reaction using the monomeric analogues. The obtained polymer is one of the new poly(thiaheterohelicene)s. Magnetic circular dichroism of the polymer suggested an electron transition ascribed to the fused-ring structure.

The pressure-sensitive paint (PSP) technique has potential as a powerful diagnostic tool for measurements in the high Knudsen number regime because it is based on luminescence of molecules. Three types or PSP [two composed of organic dye and polymer (luminophore/binder), platinum octaethylporphyrin (PtOEP)/silicone polymer (GP197) and platinumtetrakis (pentafluorophenyl) porphyrin (PtTFPP)/poly[1-(trimethylsilyl)-propyne] [poly(TMSP)], and the other ruthenium II tris (4,7-diphenyl-1, 10-phenanthrolin chloride (Bath-Ru) adsorbed on anodized aluminum] are applied to the rarefied gas flow mainly lower than 150 Pa (about 1 torr) to examine fundamental properties, such as pressure/temperature sensitivity time response of luminescence. and so on. The results show PtTFPP/poly(TMSP) to be the most suitable PSP among them for application in the low-pressure range because it has very high and linear sensitivity against oxygen pressure. However, temperature sensitivity of PtTFPP/poly(TMSP) is not negligible, and a correction of temperature is required for quantitative pressure measurement with high accuracy. Finally, pressure distribution of a surface on which a low-density supersonic freejet impinges is measured by the PSP.

A membrane having a long lifetime was prepared by spin-coating a perfluororesin on the polymer-cobaltporphyrin membrane, while the coating had no significant effect on the oxygen permeability and oxygen/nitrogen selectivity of the membrane. The oxygen-binding properties of CoP and facilitated oxygen transport of the coated membrane were also studied. It was found that CoP fixed even in the coated membrane had rapid and reversible oxygen-binding properties in response to the partial oxygen pressures and the apparent oxygen-binding equilibrium constants of CoP were not influenced by the coating. Oxygen permeation was selectively facilitated with CoP fixed in the perfluororesin-coated membrane, whereas the water vapor permeability was significantly suppressed in comparison with that of the uncoated membrane. With increasing the coating thickness, the oxygen permeability coefficients slightly decreased, but the water vapor permeability coefficients significantly decreased. The lifetime of the CoP as an oxygen-carrier in the perfluororesin-coated membrane was prolonged, which was attributed to the hydrophobic property of the coating.

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Poly[4-(N,N-bis(4-3,5-bis(3,5-bis(benzyloxy)benzyloxy)benzyloxyphenyl)amino)-1,2-phenylenevinylene] was prepared by the palladium-catalyzed polycondensation of the dendron-coupled bromostyrene and oxidized to yield the corresponding poly(aminium cationic radical): The dendron-combined polyradical molecule displayed both a substantial chemical stability and a multiplet state without any intermolecular interaction.

The electron-transfer rate constants of nitroxide derivatives, 4-(N-t-butyl-N-oxylamino)-t-butylbenzene, 4-(N-t-butyl-N-oxylamino)methoxybenzene, and 2,2,6,6-tetramethylpiperidinyl-N-oxyl, were investigated by electrochemical methods, which demonstrated that these radicals can potentially be used as a high power-rate electrode-active material due to their fast electron-transfer process.

The reversible oxygen-binding properties of the polyethyleneimine-cobalt (PEI-Co) complex and the effect of the PEI-Co complex on the reduction current of oxygen were studied. The color of the PEI-Co complex in the electrolyte solution changed on exposure to oxygen atmosphere, which was monitored by UV-visible absorption spectrometry. The UV-visible absorption spectra of the PEI-Co complex displayed a new adsorption band at 310 nm, with an isosbestic point at 280 nm. The spectral change was attributed to the reversible oxygen-adduct formation of the PEI-Co complex even in the electrolyte solution. The oxygen-binding equilibrium curve of the PEI-Co complex obeyed a Langmuir isotherm, to give the high oxygen-binding affinity ( p(50) = 0. 667 kPa). And the apparent dissociation rate constant of oxygen from the PEI-Co complex ( k(d) = 1.1 x 10(5) s(-1)) was also high. The aqueous solution of the PEI-Co complex that had rapid and reversible oxygen-binding properties functioned as an oxygen-enriching medium for oxygen electrode to enhance the diffusion-controlled current for the oxygen reduction. Based on the rapid release of oxygen from the PEI-Co complex, a high current was obtained for the reduction of oxygen in the presence of the PEI-Co complex, and the current increased with the increase of the concentration of the PEI-Co complex and the oxygen concentration in the atmosphere. The reduction current reached a saturated value near [ethyleneimine unit]/[Co] = 5, which suggested the structure of a six-coordinate mu-dioxo dinuclear complex [N5CoIII-O-2-(CoN5)-N-III]. A new type of oxygen-diffusion electrode for metal/air batteries and fuel cells is proposed using the oxygen-enriching material immobilized at the electrode surface.

Purely organic-derived nitroxide radicals, including their polymer derivative, poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), were characterized as a new class of cathode-active materials for lithium batteries. PTMA was stable at ambient conditions, had a tunable solubility and processability, and could undergo thermal runaway without any odor and ash. The nitroxide radicals displayed a reversible and very rapid redox to form their oxoammonium salts, which enabled a high power-rate performance during the charge and discharge process of the battery. (C) 2004 Elsevier Ltd. All rights reserved.

We synthesized 3-dithiolthione-substituted polythiophene, poly [3-(1',2-dithiol-3'-thione-4'-yl)thiophene], by cyclization reaction of poly [3-bis(methoxycaronyl)methyl thiophene]. Its redox behavior and electronic states showed that the oxidation of the polythiophene followed the oxidation of the dithiolthione ring to the radical cation of the dithiolthione ring.

Novel triphenylamine- and oxadiazole-substituted poly(1,4-phenylenevinylene)s (PPV) or CN-PPV (P1-4) were synthesized by the Wittig-Horner. Knoevenagel. and Gilch type polymerization. The polymers exhibited good solubility in common organic solvents, relatively high photoluminescent (PL) efficiency, and high HOMO level for ca. -5.1 eV. The simple double-layer devices of triphenylamine-PPV A1, ITO/PEDOT: PSS/P1/Cs/Al, exhibited a very high luminance of 5 10 cd/m(2) under a low driving voltage of 3 V, demonstrating the effectiveness of triphenylamine moiety as a substituent of PPV derivatives for a light-emitting polymer. Triphenylamine-CN-PPV (P2) exhibited bipolar reversible redox in CV. The bipolar type of PPVs, P2 and triphenylamine-oxadiazole-PPV (P3), showed lower luminance and efficiency than those of the p-type of PPV (P1). (C) 2004 Elsevier B.V. All rights reserved.

The redox behavior of a decavanadium complex [(V=O)(10)(mu(2)-O)(9)(mu(3)-O)(3)(C5H7O2)(6)] (1) was studied using cyclic voltammetry under acidic and basic conditions. The reduction potential of V(V) was found at less positive potentials for higher pH electrolyte solutions. The oxygen reduction at complex I immobilized on a modified electrode was examined using cyclic voltammetry and rotating ring-disk electrode techniques in the I M KOH solutions. On the basis of measurements using a rotating disk electrode (RDE), the complex I was found to be highly active for the direct four-electron reduction of dioxygen at -0.2 V versus saturated calomel electrode (SCE). The complex I as a reduction catalyst of O-2 with a high selectivity was demonstrated using rotating ring-disk voltammograms in alkaline solutions. The application of complex I as an oxygen reduction catalyst at the cathode of zinc-air cell was also examined. The zinc-air cell with the modified electrode showed a stable discharge potential at approximately I V with discharge capacity of 80 mAh g(-1) which was about five times larger than that obtained with the commonly used manganese dioxide catalyst. (C) 2004 Published by Elsevier B.V.

Modified poly(methacrylic acid) microparticles complexed with gadolinium(III) (Gd3+) ions were prepared in 100 nm. The emulsion terpolymerization of methacrylic acid, ethyl acrylate, and allyl methacrylate and the following complexation with Gd3+ ions yielded the polymer particles with different Gd3+ ion contents. Potentiometric titration of the complexation of the particle with Gd3+ ions indicated the formation of a very stable tris-carboxylate coordinate complex with the Gd3+ ion. Electron spin resonance and IR spectra of the complexed particles were dependent on the Gd3+ ion content and the coordination environment in each particle. The microparticles dispersed on a mica substrate were subjected to atomic force microscopy (AFM), followed by magnetic force microscopy (MFM). AFM showed 100-nm-sized and monodispersed spherical images. The following MFM clearly provided strong magnetic responses exactly on the same particle positions, of which the images were also dependent on the Gd3+ ion content in the particle. (C) 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1912-1918, 2004.

Nanometer-sized polystyrene particles were selectively deposited by interfacial tension in nanometer-sized etchpit arrays made on a silicon substrate.

A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekule- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-NN-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements.

Cobalt complexes that reversibly bind and release O-2 functioned as O-2 carriers, or O-2-enriching media, at the surface of a cathode to enhance the current for the reduction of O-2. The effect of the cobalt complex to accumulate O-2 was evidenced by the higher open-circuit potential, which reflected the equilibrated concentration of O-2 at the electrode surface. The combination of the cobalt complex and the conventional Pt/C catalyst resulted in a significant increase in the steady-state Current for the four-electron reduction of O-2, particularly at small overpotentials where typical fuel cells operate, based on the facilitated transport of O-2 from the atmosphere to the catalyst at the electrode Surface.

The stability of some porphyrin-calix[4]arene sodium-ion complexes were determined by a collision-activated decomposition (CAD) method utilizing electrospray ionization mass spectrometry (ESI-MS). Comparing the values of E-1/2, the collision energy at which the relative intensity of the complex ion is 0.5, we found that the porphyrin-calix[4]arene complex with the higher value of E-1/2 corresponded to that with the larger association constant (K-ass), as measured by H-1-NMR in CDCl3. Both our ESI-MS and NMR studies proved that the number of hydrogen bonds and the rigidity of the calix[4]arene stabilized the complex. The ESI-MS technique could be successful in screening the binding affinity in host-guest systems with a small amount of sample. Copyright (C) 2004 John Wiley Sons, Ltd.

The reversible oxygen-binding properties of tetraphenylporphyrinatocobalt(II) (CoTPP) complexed with poly(3,4-azopyridylene) ( PAP) were established. The CoTPP complexes functioned as oxygen carriers at the surface of a cathode to enhance the current for the reduction of oxygen. PAP was synthesized by the oxidative polymerization of 3,4-diaminopyridine in a DMF solution at 25degreesC using a Cu/pyridine catalyst. The combination of the CoTPP complex and the conventional Pt/C catalyst resulted in a significant increase in the steady-state current for the four-electron reduction of O-2, particularly at small overpotentials where typical fuel cells operate, based on the facilitated transport of O-2 from the atmosphere to the catalyst at the electrode surface.

5-(4-Trimethylsilyethynylphenyl)-10,15,20-triphenyiplatinumporphyrin was synthesized and copolymerized with trimethylsilylpropyne to give a new high-molecular-weight porphyrin polymer. The polymer formed a smooth and tough coating on many types of surfaces. The coating showed a strong blue luminescence from the platinumporphyrin residue which was quenched in the presence of oxygen. The relationship of the luminescence intensity vs oxygen pressure displayed a remarkably high pressure sensitivity in the low oxygen pressure area, which was ascribed to the high oxygen permeability of the polymer.

A series of membranes having a selective and reversible oxygen-binding capacity were prepared by complexing picket-fence cobaltporphyrin (CoP) as an oxygen carrier with various polymer matrixes. The oxygen-absorption isotherm and oxygen permeation in and through the membranes were properly analyzed by dual-mode models to give the physical solubility coefficient of oxygen (k(D)), the physical diffusion coefficient of oxygen through the membrane (D-D), and the apparent diffusion coefficient of oxygen for hopping between fixed carriers (D-C). The oxygen-binding equilibrium constant (K) of CoP was independent of the polymer matrix species. The D-C value was smaller than the D-D value, but the D-C/D-D ratio still remained in the range of 1/5-1/50, indicating that CoP fixed in the membrane reversibly binds oxygen and facilitates oxygen transport.

meso-Tetra(2-pyridyl)porphyrin forms a duplex with tetrahydroxylealix[4]arene via triplicate or quadruple hydrogen bonds, to provide a capping structure on the porphyrin plane.

By the density-functional-derived tight-binding method, the electronic transport properties of two types of benzothiophene-based molecular wires, i.e., the linear and helical molecular wires have been investigated. In the molecular bridge system where these molecules are connected to the gold electrodes by S-Au bonds, the transmission peaks are found to lie at the energies somewhat lower than 0.5 eV below the Fermi level for both cases. Thus the conductances of both types of wires for the bias voltage less than 1.0 V are not so large without doping. Upon iodine doping, however, the new transmission peaks are found to appear around the Fermi level, particularly in the case of helical wires. It means that the conductances of the helical wires are expected to be improved dramatically by the chemical doping. Therefore, the doped helical molecular wires are predicted to work as molecular solenoids even under lower bias voltages. Next, the applicability of the current-induced magnetic field generated in such a molecular solenoid is considered. As an example, we propose a novel helical molecule where the hydrogen atoms connected to the inner C-C bonds of the helix are substituted by some kind of radicals. In this case the current-induced field can control the alignment of the radical spin orientations. (C) 2003 American Institute of Physics.

Depolymerization of an engineering plastic, poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), was accomplished by using 2,6-dimethylphenol (DMP) under oxidative conditions. The addition of an excess amount of DMP to a solution of PPO in the presence of a CuCl/pyridine catalyst yielded oligomeric products. When PPO (M-n = 1.0 X 10(4), M-w/M-n = 1.2) was allowed to react with a sufficient amount of DMP, the molecular weight of the product decreased to M-n = 4.9 X 10(2) (M-w/M-n = 1.5). By a pro-longed reaction with the oxidant, the oligomeric product was repolymerized to produce PPO essentially identical to the starting material, making the oligomer useful as a reusable resource. During the depolymerization reaction, an intermediate phenoxyl radical was observed by ESR spectroscopy. Kinetic analysis showed that the rate of the oxidation of PPO was about 10 times higher than that of DMP. These results show that a monomeric phenoxyl radical attacks the polymeric phenoxyl to induce the redistribution via a quinone ketal intermediate, leading to the substantial decrease in the molecular weight of PPO, which is much faster than the chain growth.

A series of triarylamine polymers were prepared by palladium-catalyzed polycondensation. Extension of the pi-conjugation was analyzed by UV and electrochemical measurements, which revealed the degree of off-coplanarity in the polymer framework. Chemical oxidation of the polymer with NOPF6 gave the corresponding poly(aminium cationic radical). The ESR signal at room temperature indicated an exchange interaction between the radicals in the polymer. The spectrum recorded at 12 K displayed a DeltaM(s) = +/-2 transition signal at half-field, which was characteristic of multiplet species. (C) 2003 Elsevier Science Ltd. All rights reserved.

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High molecular weight and networked aromatic polyamines prepared by palladium-catalyzed polycondensation were oxidized to yield the corresponding poly(aminium cationic radical)s, which displayed a substantial stability and an intramolecular ferromagnetic interaction of eight or nine spins.

A polyelectrolyte containing a sulfonium cation, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene trifluoromethanesulfonate) (1) was tested as a separator in a zinc-air cell. In comparison with the commercially available separators such as polypropylene, polysulfonium 1 was highly effective to prevent cation permeation from the anode to cathode and effectively increased the capacity six-fold greater than that of polypropylene during discharge. This phenomenon was explained by the ion-exchange process of the membrane 1, which showed an anion-permselectivity toward OH- at low KOH aqueous solution concentrations (<1 M). (C) 2003 Elsevier Science B.V. All rights reserved.

Magnetic force microscopy (MFM) was applied to study both the molecular image and the magnetic response of pi-conjugated, non-Kekule-, and nondisjoint-type poly(1,2-phenylenevinylene) (nondisjoint refers to a molecule in which non-bonding molecular orbitals share the same region in the molecule and a multiplet ground state is significantly stabilized) networks bearing 4-substituted di-tert-butylphenoxyl moities. The polyphenoxyl radicals 1 with molecular weights of 2.6, 9.3, and 32 kDa have a substantial stability even at room temperature and in air, and molecular sizes in the nanometer range of 10, 20, and 35 nm, respectively, with a disk-like shape. The MFM clearly shows a magnetic gradient response exactly on the position of the polyradical molecule dispersed on a graphite surface. The MFM molecular image of polyradical samples with different molecular weights and spin concentrations was examined as a nanoscale and single-molecular-based magnetic dot.

The oxidizing process and the oxygen-binding lifetime of, 5, 10, 15, 20-tetra (o-pivalamidophenyl)- porphyrinato cobalt(II) (TPPCo) complexed with poly (vinylimidazole-co-fluoropentyl methacrylate) (PFIm) Were studied,and the mechanism and dynamics of irreversible oxidation of TPPCo were discussed. The TPPCo displayed a reversible change in the UV-visible absorption spectrum from the deoxy form (lambda(max) = 530 nm) to the oxygen-binding one (lambda(max) = 548 nm) with an isosbestic point at 538 nm, in response to the partial oxygen pressure of the atmosphere. But the active TPPCo complex in the membrane was slowly changed, via the irreversible oxidation reaction in the open atmosphere, to the TPPCo (III) complex without the oxygen-binding ability, which could be monitored by the UV-visible absorption at lambda(max) = 548 nm. In the solid membrane state, water molecules in air may attack the TPPCo-bound dioxygen to yield a hydrodioxy radical and TPPCo ( III), which is the main reason that diminishes the oxygen-binding ability of the TPPCo complex and that of the membrane. The half-lifetime (tau) of the TPPCo complex as an oxygen earner was measured by allowing the TPPCo-PFIm membrane to stand in dry air (environmental humidity 10%) in laboratory air (humidity ca. 50%) and in a water vapor atmosphere (humidity 95%) at room temperature, respectively. The decrease course of the active TPPCo complex approximately follows the first-order kinetics and gives the t values. The tau value of the PFIm-TPPCo complexed. membrane was as long as ca. 250 days even in the water vapor-saturated atmosphere. Under the same laboratory air condition, the lifetime of the PFIm-TPPCo membrane was much longer (ca. 13 times) than that of the reference non-fluoro membrane such as the membrane of TPPCo complexed with poly(octyl methacrylate-co-vinylimidazole). The hydrophobic property of the PFIm polymer is considered to suppress the irreversible oxidation of the active TPPCo carriers caused by water molecules and to significantly prolong the operational lifetime of the TPPCo complex membrane.

Nanometer-sized polymer particles bearing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals were prepared. The emulsifier-free emulsion polymerization of methacrylic acid, methyl methacrylate, and methylenebisacrylamide and the following introduction of the TEMPO moiety produced polyradical particles with different spin concentrations. The TEMPO-combined particle was also prepared in one step by the anionic dispersion polymerization of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The position and horizontal shape in the atomic and magnetic force microscopic images of the polyradical particle coincided with each other. The vertical scale of the magnetic image responded to the spin concentration of the particle. The particle bearing the radicals on its surface gave a hollow dot image.

A cationic polyelectrolyte of various poly(arylenesulfonium salt)s were coated on the surface of glassy carbon electrodes with an incorporated ferricyanide anion from the electrolyte solutions. The apparent diffusion coefficients of Fe(CN)(6)(3-), that are electrostatically bound were determined by chronoamperometry, chronocoulometry and mediated electron transfer from the rotating disk voltammetry. The complex incorporated by the S-cationic polyelectrolyte shows a high diffusion coefficient for the polyelectrolyte of poly(methylsufonio-1,4-phenylenethio-1,4-phenylene trifluoromethanesulfonate). The diffusion of poly(arylenesulfonio triflate) depended on the ionic exchange of the S-cation which has an alkyl bond and the crystalline structure that influenced the electrostatic motion of the anion within the polyelectrolyte modified electrode.

An engineering plastic, poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), was prepared via oxidative polymerization in water. 4-(2',6'-Dimethylphenoxy)-2,6-dimethylphenol was stirred in an aqueous alkaline solution with a metal catalyst to yield PPO with a molecular weight of three to four thousand. The formation of diphenoquinone as the side-product was inhibited in this reaction. This reaction is slow but also proceeded under oxygen without a catalyst. The oxidative polymerization in water provides a new polymerization procedure for PPO.

meso-Tetrakis(alpha, alpha, alpha, alpha-o-pivalamidophenyl)porphinatoiron(II) derivative is incorporated into thermophilic xylanases, giving novel thermostable synthetic hemoproteins, which can form a dioxygen adduct in aqueous media (pH 7.3) at 90 degreesC.

alpha-Cyclodextrin (alphaCD)-penetrating 2-methyl-1-phenethylimidazole coordinates to the zinc(II) and iron(II) complexes of meso-tetrakis[o-(N-methyl) pyridinium] porphyrinate, giving non-covalently linked alphaCD-porphyrin ensembles; the iron(II) complex can reversibly bind and release dioxygen in aqueous DMF solution.

Synthesis and characteristics of poly ( fluoropentyl methacrylate-co-vinylimidazole) (Flm), and oxygen-binding properties of its complex with meso-a, a, a, a-tetrakis(o-pivalamidophenyl) porphyrinato cobalt(II) (CoP) were studied. FIm was prepared by radical copolymerization of octafluoropentyl methacrylate with 1-vinylimdazole using azobis( isobutyronitrile) as the initiator. The vinylimidazole content and molecular weight of the Flm copolymer were determined to be 25 mol% and 5.0 x 10(4) by elemental analysis and GPC, respectively. Flm and CoP in solution were mixed to complex the imidazolyl residue of the copolymer with the fifth coordination site of CoP under nitrogen atmosphere to yield both an active and homogenous dispersed CoP for oxygen-binding. Oxygen-binding to the CoP-FIm complex was measured spectroscopically with a UV spectrophotometer. The CoP-FIm complex displayed a reversible change in the visible absorption spectrum from the deoxy form to the oxy or oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-binding equilibrium curves obeyed a Langmuir isotherm, to give the oxygen-binding affinity p(50) (oxygen partial pressure at which half of the CoP binds with oxygen). Solvent has great effect on the oxygen-binding properties of the complex. The oxygen-binding affinity of the CoP-FIm complex in tetrahydrofuran was larger than that in N, N-dimethyl formamide solution. It is assumed that a N, N-dimethyl formamide molecule weakly coordinated to the sixth site (oxygen-binding site) of Cop to reduce the oxygen-binding affinity. On the other hand, the oxygen-binding site of the CoP complex could be maintained vacant in tetrahydrofuran before the oxygen-binding. The binding and dissociation rate constants of oxygen to and from the CoP (k(on) and k(off), respectively) for the CoP-FIm solution were large, which indicates a very rapid and reversible oxygen-binding by CoP.

Reversible oxygen-binding was observed at low temperature for the poly(vinylimidazole-co-octyl methacrylate) complexes of the simple or planar cobaltporphyrins (CoP) such as cobalt-tetraphenylporphyrin and cobalt-octaethylporphyrin. The oxygen-binding affinity and rate constants were compared with those for the cobalt-picketfence porphyrin, a typical oxygen-carrier. The low oxygen-binding affinity for the CoP complexes was attributed to the enormously large oxygen-releasing rate constant.

The picket-fence cobaltporphyrin (Col?) having rapid and reversible oxygen-binding properties was employed to accumulate oxygen from a bulk solution to a diffusion layer at an electrode surface. Modification of a carbon electrode with a thin CoP liquid membrane resulted in a significant increase in the reduction current of oxygen, which proved to be a new type of modified electrode to reduce the diffusion resistance of oxygen from the bulk solution onto the electrode surface.

A highly gas permeable polymer, poly(1-trimethylsilyl-1-propyne) (poly(TMSP)), was applied as a matrix of the optical oxygen sensor using the oxygen-induced luminescence quenching of octaethylporphyrin (OEP) platinum (PtOEP) or palladium complex (PdOEP). OEP complex was homogeneously dispersed in poly(TMSP) to give a mechanical tough film with thickness of 10 mum. The luminescence intensity of OEP complex dispersed in the poly(TMSP) films drastically decreased with an increase in oxygen concentration. The oxygen sensitivity of the film (I-0/I-100) was very high and estimated to be 225 for PtOEP and 121 for PdOEP, respectively. The Stern-Volmer constants of PtOEP and PdOEP dispersed in poly(TMSP) films are estimated to be 6.6 and 17%(-1), respectively. These results indicate that OEP metal complex dispersed in the poly(TMSP) films are novel optical sensing material for trace analysis of oxygen.

Recently pressure sensitive paint (PSP) has actively developed to measure continuous distribution of the surface pressure. However, the pressure range has been limited above l Torr (133.3 Pa) and there is no application to lower pressure range because the pressure sensitivity seems to be not so high in that range. In this study, we apply three types of PSP [two types are composed by organic dye and polymer (luminophore/binder)
PtOEP/GP 197 and PtTFPP/poly(TMSP), and another one is Bath-Ru adsorbed on anodized aluminum] to the rarefied gas flow mainly lower than l Torr and examine those fundamental properties, such as pressure/temperature sensitivity and time response of luminescence and so on, leading to selection of the most suitable PSP among them for the low pressure range. Finally, the pressure distribution of the surface on which a low density supersonic free jet impinges is measured by the PSP.

A pi-conjugated but non-Kekule- and nondisjoint-type molecule, poly(1,2-phenylenevinylene) 3,5-disubstituted with pendant phenoxyl radicals (1a), was designed as a new high-spin organic polymer and synthesized by the head-to-tail coupling polymerization of 2-bromo-3,5-bis(3,5-di-tert-butyl-4-aceotoxyphenyl)styrene (3) using a palladium catalyst. The corresponding high-spin dimer model compound bearing four phenoxyl radicals (2a) was also synthesized. The stepwise radical formation in 1 and 2 was electrochemically studied. The ESR signal at DeltaM(s) = +/-2 indicated a triplet ground state for 1 and 2. However, the SQUID data revealed that the spin concentration and the average spin quantum number of la and 2a remained at ca. 0.5 spin/phenol unit and 2/2, respectively. A degradation at the vinylene bridge was suggested after the radical generation.

A thin membrane of the cobalt-tetraphenylporphyrin (CoTPP) complex with the copolymer of octyl methacrylate and vinylimidazole (OIm) was successfully prepared with the thickness of 80similar to90 nm on a porous support membrane. The cobaltporphyrin-highly loaded membrane showed a high performance in the facilitated transport of oxygen. Homogeneous distribution of the CoTPP throughout the membrane and complexation with the imidazolyl residue of OIm with a 5-coordinated structure are described.

A novel pressure-sensitive paint (PSP) formulation suitable for use in cryogenic and unsteady wind-tunnel testing has been developed. This new PSP uses poly [1-(trimethylsilyl)-1-propyne] [poly(TMSP)] as a binder. Poly(TMSP) is a glassy polymer having extremely high gas permeability. Unlike the conventional polymer-based paints, PSP based on poly(TMSP) maintains oxygen sensitivity even at cryogenic temperatures and exhibits fast response time. This paint is sprayable on any model surface including stainless steel and ceramics. These capabilities allow us to apply this PSP to a cryogenic wind tunnel and a short-duration shock tunnel. To demonstrate the capability of poly(TMSP)-PSP for pressure measurements in a cryogenic wind tunnel, a circular-arc bump model and a delta wing model were tested in the National Aerospace Laboratory 0.1-m Cryogenic Wind Tunnel at 100 K. It has been verified that poly(TMSP)-PSP can provide high SIN pressure distribution data at high O-2 concentration. A comparison of the measured intensity data with the pressure tap measurements has suggested that the in situ calibration can be used to obtain quantitative pressure data. It was also demonstrated that poly(TMSP)-PSP could visualize the complex flowfield on a stainless steel delta wing, including primary and secondary separation vortices and their breakdown.

An aqueous solution of a [poly(ethyleneiminato)]cobalt(II) complex that reversibly binds and releases O-2 functions as an O-2-enriching medium for an O-2 electrode to enhance the current for the uncatalyzed reduction of O-2. The effect of the electrochemically inactive cobalt complex is to supply reducible O-2 to the solution within the diffusion layer near the electrode by releasing the bound O-2 from the O-2 adduct, which contributes to a decrease in the diffusion layer thickness of O-2. Based on the rapid release of O-2 from the O-2 adduct, a diffusion-limited current is obtained for the reduction of O-2. The hypothetical concentration of the enriched O-2 supplied under pure diffusion control (i.e. unperturbed by the kinetics of the O-2 binding) is several times larger than that of the actual concentration of O-2 due to the higher solubility of the O-2 adduct than the physical solubility of O-2 in H2O at room temperature under an atmosphere of air. An insoluble membrane of a cobalt( II) complex with a cross-linked poly( ethyleneimine) ligand that has the ability to swell serves as an O-2-enriching material to concentrate O-2 from aqueous electrolyte solutions. A new type of O-2-diffusion electrodes for metal/air batteries and fuel cells is proposed using the O-2-enriching material immobilized at the electrode surface.

2,6-Dibromo-4-(3',5'-di-tert-butyl-4'-acetoxyphenyl) styrene was polymerized in a one-pot reaction using a palladium catalyst, and subsequent hydrolysis and oxidation yielded the hyperbranched poly[(4-(3',5'-di-tertbutyl- 4'-ylooxyphenyl)-1,2,(6)-phenylenevinylene)], which three-directionally satisfies both an alternant but non-Kekule-type pi-conjugation and the ferromagnetic connectivity of the unpaired electrons of the pendant phenoxyl. The AFM image, unusually low solution viscosity, and low chemical reactivity of the phenol group indicated the polymer to have a highly branched and globular structure. In spite of the extremely crowded branching, pi-conjugation in the polymer skeleton was maintained, as indicated by photoelectron and EPR spectroscopies. The phenoxyl polymer even with a spin concentration of only 0.4 spin per monomer unit displayed an average S value of 3.

A series of pi-conjugated polymers alternatively involving m-phenylenevinylene or p-phenylenevinylene and a triphenylamine moiety in the main chain, poly(triphenylamine-alt-phenylenevinylene)s, were synthesized and their optical and electrolumienscent properties were studied. Single-layer light-emitting diodes based on each polymer showed a strong blue-yellow-green emission ascribed to their band gaps, and exhibited small turn on voltages and large current densities. The device containing poly(4-methyltriphenylamine-alt-p-phenylenevinylene) (MPA-pPV) displayed a high brightness (640 cd/m(2) at 10 V). These results suggest that the polymers have a good charge transporting ability, and an electroluminescent property.

Radical groups, tert-butylnitroxide, nitronyl nitroxide, and 2,6-di-tert-butylphenoxyl, were introduced at the 3-position of thiophene, and the thiophene derivatives were then polymerized to yield poly(3-radical-substituted thiophene)s. The acetoxyphenyl-substituted thiophene gave regio regular poly(3-phenol-subslituted thiophene) via oxidative polymerization with ferric chloride at low temperature, while the polymerization of the amine-substituted thiophenes did not proceed with any oxidizing agents under any reaction conditions. The phenoxyl-substituted polyradicals, 7 and 8, with spin concentrations of 0.30 and 0.25, respectively, displayed S values of 2/2 to 3/2 and 2/2, respectively, indicating an intramolecular ferromagnetic spin-coupling through the polythiophene backbone. The polyradicals, 7 and 8, themselves and the polyradical doped with iodine showed an electrical conductivity of 10(-5) and 10(-2 similar to) (-1) S cm(-1), respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.

5,4'-Bis[bis(p-methoxyphenyl)amino]-2-methoxystilbene (1) was synthesized. The electrochemical and chemical oxidations of 1 produced its cationic biradical, which was studied in comparison with the biradical derived from the analogue 2 without the 2-methoxy substituent. The biradical of 1 exhibited substantial chemical stability, because the reactive 2-position of a 5,4'-biradical-substituted stilbene is effectively blocked in 1 with the methoxy substituent. However, the 2-substituent caused a torsion in the stilbenoid pi -conjugated framework to weaken its ferromagnetic coupling ability. (C) 2001 Elsevier Science Ltd. All rights reserved.

A membrane having both a selective oxygen-absorbing capability and a long operational lifetime was prepared by complexing picket-fence cobaltporphyrin (CoP) with poly(vinylimidazole-co-fluoropentyl methacrylate) (FIm) as a polymer-ligand. The oxygen-binding affinity of the CoP complexed in the membrane was larger than that in the solution state. Oxygen permeation was selectively facilitated with the CoP fixed in the membrane, and a high oxygen permeability (10(-7) cm(3)(STP) cm cm(-2) s(-1) cmHg(-1)) maintaining the permselectivity was observed. The lifetime of the CoP as an oxygen-carrier was prolonged by complexing with FIm even in a humid atmosphere (half-lifetime > 200 days) due to the hydrophobic property of the FIm copolymer.

3-{4-[(3,5-Di-tert-buty1-4-acetoxyphenyl)(3,5-di-tert-buty1-4-oxocyclohexa-2,5-diene-1-ylidene)methyl]phenyl} thiophene (2a) was synthesized and oxidatively polymerized with ferric chloride at low temperature to yield poly (3-{4-[(3,5-di-tert-buty1-4-acetoxyphenyl)(3,5-di-tert-buty1-4-oxocyclohexa-2,5-diene-1-ylidene)-methyl]phenyl} thiophene) (1a), Head-to-tail content of 1a with a molecular weight of > 10(4) reached 92%. This polymer has a quinoid chromophore, and it reversibly showed a dark blue and red brownish color ascribed to an anion and a radical form, respectively. The polyradical 1 was almost quantitatively generated from 1b (a spin concentration of 0.9 spin/galvinoxyl unit), which was persistent at room temperature. The SQUID measurement at low temperature gave a spin quantum number (S) of 1/2 for 1, which indicated a paramagnetic ground state. 1 doped with iodine showed an electrical conductivity of 10(-5) S cm(-1). The polyradical derivatives, 7 and 8, displayed S of 1/2-2/2 and 1/2, respectively, and an electrical conductivity of 10(-4)-10(-3) S cm(-1) after doping.

Conjugated polymers alternatively involving m-phenylenevinylene or p-phenylenevinylene and a triphenylamine moiety in the main chain were synthesized via a Wittig-Horner-type polycondensation of 4-diformyl-4',4 " -dimethyl-triphenylamine or 4-diformyl-4',4 " -dimethoxy-triphenylamine with m-xylene-bis(diethylphosphonate) or p-xylene-bis(diethylphosphonate). A high glass-transition temperature (ca. 120 degreesC) and thermal stability (5% weight loss at temperatures greater than 450 degreesC) were observed for all polymers. These polymers, especially poly(methyltriphenylamine-alt-p-phenylenevinylene), fluoresced a strong green color under UV irradiation, with a quantum efficiency of 50% for their chloroform solutions. Cyclic voltammetry showed a relatively low ionization potential (5.18-5.44 eV) for the polymers. These results suggest that these polymers satisfied the requisites of polymer materials for a single-layer light-emitting diode. The aminium radical derived from the oxidation of poly(triphenylamine-alt-m-phenylenevinylene) satisfied both non-Kekule-type pi conjugation and ferromagnetic connectivity of the unpaired electrons and displayed a multiplet ground state. (C) 2000 John Wiley & Sons, Inc.

Poly[3-(3',5'-di-tert-butyl-4'-acetoxyphenyl)thiophene] (la) was regioselectively synthesized via simple oxidative polymerization of 3-(3',5'-di-tert-butyl-4'-acetoxyphenyl)thiophene (2a) with ferric chloride. Head-to-tail content of la with a molecular weight of >10(4) reached 96% by modulating both the polymerization conditions and the purification procedure of the polymer. Visible absorption and fluorescence maxima were bathochromically shifted for both la and poly[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)thiophene] (Ib), which suggests an extended pi -conjugation, i.e., a regioregular structure. Redox of the phenolate and of the thiophene residue of Ib was observed reversibly and independently under alkaline conditions. The polyphenoxyl 1 derived from the oxidation of Ib showed an electrical conductivity of 10(-5) S cm(-1). The polyradical 1 satisfies both an alternant but non-Kekule-type pi -conjugation and ferromagnetic connectivity of the unpaired electrons of the pendant phenoxyls. 1 with a spin concentration of 0.3 spin/unit displayed a spin quantum number (S) value of 2/2 to 3/2, indicating a high-spin ground state and an intramolecular ferromagnetic spin coupling through the polythiophene backbone.

Red-colored and solvent-free membranes based on the picket fence cobaltporphyrin (CoP) complexed with two or three kinds of polymer-ligands were prepared, and their visible absorbance responses to oxygen partial pressure were studied. The four CoP complexes with copolymers of 4- and 1-vinylimidazole and 4- and 2-vinylpyridine as a polymer-ligand were characterized by different oxygen affinity: In this order of the copolymers, the oxygen affinity of CoP was decreased by a factor of 10. The membrane composed of the three CoP complexes displayed a selective and continuous response in the visible absorbance ascribed to the oxygen-adduct formation over a wide range of oxygen partial pressure, i.e., 0.01-76 cmHg at atmospheric total pressure. On the other hand, the membrane composed of the two complexes with strong and weak affinity responded in a stepwise manner to oxygen partial pressure. The CoP complexed with and fixed in the polymer-ligands could form an oxygen adduct rapidly and reversibly just as the CoP complex did in a solution. The oxygen response rate of the membrane was shortened inversely with the square root of its thickness. The operational lifetime was longer than 1 month, which was much prolonged for the CoP complexed with the fluoroalkyl methacrylate copolymers: The latter also displayed a selective and reversible oxygen response in water.

3,3'-Bis[bis(p-t-butylphenyl)amino]stilbene 1a and 3,4'-bis[bis(p-methoxyphenyl)amino]stilbene 1b were synthesized. The oxidation of 1 was analyzed by electrochemical measurements, which revealed the reversible formation of the bis(cation radical) 2 via a two-electron transfer reaction. The chemical oxidation of 1 with NOBF4 also gave the bis(cation radical) 2; UV/vis and ESR spectroscopies supported aminium radical formation without any side reaction. Magnetization, magnetic susceptibility, and the ESR Delta M-s = +/-2 signal of the biradicals indicated tripler ground states with a large triplet-singlet energy gap.

The oxygen-binding affinity of the cobalt-picketfence-porphyrin (CoP) ligated with imidazole was enhanced in the presence of an additive which forms a hydrogen-bond with the ligated imidazole. The CoP complex with poly(4(5)-vinylimidazole-co-octylmethacrylate) rapidly and reversibly bound oxygen and showed very high oxygen-binding affinity. The oxygen transport in the CoP-polymer membrane was efficiently facilitated.

A highly gas permeable polymer, poly(1-trimethylsilyl-1-propyne) (poly(TMSP)), was applied as an optical oxygen sensing matrix using luminescence quenching of platinum octaethylporphyrin (PtOEP) by oxygen. PtOEP was homogeneously embedded in poly(TMSP) to give a mechanically tough film with a thickness of 10 mum. The luminescence intensity of PtOEP embedded in the poly(TMSP) film drastically decreased with an increase in oxygen concentration. The oxygen sensitivity of the film (I-0/I-100 ) was very high and estimated to be 225. The Stern-Volmer plot for the poly(TMSP) film-embedded PtOEP was obeyed at lower oxygen concentrations between 0 and 10% and the Stern-Volmer constant is estimated to be 5.7%(-1). The limit of oxygen detection was less than 0.3%. The response times of PtOEP embedded in the poly(TMSP) film are 3.6 s on going from argon to oxygen and 73.2 s on going from oxygen to argon, respectively. These results indicate that PtOEP embedded in the poly(TMSP) film is a novel optical sensing material for trace analysis of oxygen.

5,10,15,20-Tetrakis(alpha-o-pivalamidophenyl)porpphyrinatcobalt(II) (CoP) complexed with N-tritylimidazole in the solid state quickly and reversibly absorbed oxygen from air (14 cm(3) O-2/g), which was ascribed to a Co/dioxygen 1/1 adduct formation. The adduct formation was an exothermic reaction, and the absorbed oxygen was released above 65 degrees C. A disk (e.g., diameter 2 cm x 2 mm) was prepared with powders of the oxygen-absorbing, but electrically insulating, CoP complex and of electrically conductive carbon. The application of 1.5 V to the disk induced a temperature elevation in the disk, which momentarily released the absorbed oxygen. The oxygen-releasing and -absorbing cycle could be repeated more than 100 times, with a 5-min switching on-off interval under ambient conditions.

Poly(3,4-azopyridylene) was prepared and complexed with picket-fence coaltporphyrin; the polymer complex displayed both the selective and reversible oxygen-binding and the electroconductivity of 10(-5) S cm(-1).

A new set of pi-conjugated and alternant but non-Kekule-type di- and tri(1,2-phenyleneethynylene)s pendantly substituted with phenoxyl radicals at the 4 positions (1a, 2a, and 3a) was synthesized. The synthesis of these acyclic and cyclic compounds was achieved through the head-to-tail coupling of a-bromo(or -iodo)-4-[3',5'-di-tert-butyl-4'-trimethylsiloxyl(or-hydroxy)phenyl]-1-ethynylbenzenes. The di- and triphenoxyl compounds (1a, and 2a and 3a) were triplet and quartet at the ground state, respectively, which was ascribed to a ferromagnetic coupling effect of the diphenyl ethynylene bridge for the pendant phenoxyls' spins. The cyclic pi-conjugation in 3a exhibited a stronger effect on the spin alignment.

Rodlike poly(1,4-phenyleneethynylene) fl-substituted with multiple pendant phenoxyls 1 was synthesized by polymerizing 4-bromo-2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethynylbenzene 10a using the catalyst of a palladium-triphenylphosphine complex and cuprous iodide and subsequent heterogeneous oxidation. The corresponding dimer 2 was also synthesized; X-ray analysis of its precursor 4 indicated a linear phenyleneethynylene backbone and twisted dihedral angles of 50 and 77 degrees for the pendant phenol groups, ESR spectra suggested a delocalized spin distribution from the pendant phenoxyl to the backbone. The diphenoxyl 2 had a triplet (S = 2/2) ground state. The spin concentration of the polyphenoxyl 1 could not be increased beyond 0.7 spin/unit due to its low solvent solubility; 1 with a spin concentration of 0.62 had an average S of 3/2.

Polycaprolactone is one of the biodegradable polymers with good drug permeability. In the present paper, polycaprolactone and three kinds of copolycaprolactone-polycaprolactone-poly(ethylene oxide)-polycaprolactone triblock copolymer (PCE), polycaprolactone/polycaprolactone-poly(ethylene oxide)/polylactide tricomponents random block copolymer (PCEL) and polycaprolactone/poly(ethylene terephthalate) random block copolymer (PETCL)- were synthetized. The biodegradation behavior of these polymers were shown by degradation tests in vitro, ex vivo and in vivo. The oxygen permeabilities of these polymers were in the range of 10(-10) similar to 10(-9) cm(3) (STP) cm/cm(2) sec cm Hg. Copolymers PCE and PCEL displayed O-2 and N-2 permeability coefficients (PO2/PN2) ratios of about 9. The effects of composition and crystallinity of the copolymers on biodegradability and the oxygen permeability of the polymer were discussed. Copyright (C) 1999 John Wiley & Sons, Ltd.

The polymer-supported N,N'-di(salicylidene)ethylenediaminatocobalt(II) [Co(salen)] took up oxygen through 2/1 Co/dioxygen adduct formation. The composite film of the polymer-supported [Co(salen)] and polymer layers reversibly bent under an oxygen and nitrogen atmosphere. The stretching was caused by a structural change in the [Co(salen)] crystal before and after the oxygen-binding, which was analyzed based on the near-IR spectral and density change as well as EXAFS.

A ground state quartet molecule, 2, 8, 14-trisoxyphenyltri-benzotrisdehydro[12]annulene, was synthesized; the dehydro-annulene acted as an effective ferromagnetic coupler for the pendant spins.

Some non-Kekule-type organic molecules exhibit a high-spin state based on an intramolecular spin-exchange interaction. These high-spin molecules can be extended to the corresponding polyradicals with spins that are ferromagnetically aligned. Poly(4-oxyphenyl-1,2-phenyleneethynylene) was synthesized, and the effect of the head-to-tail connectivity on the ferromagnetic interaction is described.

4-[(3,5-Di-tert-butyl-4-hydroxyphenyl)(3 2,5-di-tert-butyl-4-oxo-cyclohexa-2,5-dienylidene)methyl]styrene (abbreviated as (p-vinylphenyl)hydrogalvinoxyl) was polymerized using AIBN as an initiator to give a bright yellow polymer with <(M)over bar (w)> = 3.2 x 10(4). The polymer was oxidized to give the corresponding polyradical derivative, whose spin concentration could be increased up to about 70 mol % depending on oxidative conditions. ESR signal line-width in the solid state was greatly increased below 200 K for the polyradical with a high spin concentration (> 50 mol %). The magnetization and magnetic susceptibility indicated weak antiferromagnetic interaction among the radical sites. (C) 1999 John Wiley & Sons, Inc.

A combination membrane having both gas barrier properties and selective oxygen-absorbing and -carrying capability was prepared by complexing poly(vinylidene dichloride-co-vinylimidazole) and meso-tetrakis(alpha,alpha,alpha,alpha-o-pivalamidophenyl)porphyrin (CoP). The vinylidene dichloride copolymer was selected because of its low physical gas permeability and its dense and tough thin-membrane formability even after the CoP complexation. Oxygen permeation was selectively facilitated with the CoP carrier fixed in the membrane, and high oxygen permselectivity (facilitation factor > 25, oxygen/nitrogen permselectivity > 100, permeability 10(-10) cm(3) (STP) cm cm(-2) s(-1) cmHg(-1)) was observed, e.g., for the membrane containing > 20 wt % CoP at an upstream oxygen partial pressure of 0.5 cmHg. The facilitated oxygen transport was properly analyzed by a dual-mode model to give permeation parameters of the membrane such as the postulated diffusion coefficient of oxygen hopping via the fixed CoP carrier (D-C). D-C was inversely proportional to the average distance between the CoP carrier sites.

Star-shaped poly(1,2-phenylenevinylene)s 4-substituted with multiple pendant phenoxyls (2 and 3) were synthesized by polymerizing 2-bromo-4-(acetoxyphenyl)styrene in the presence of 1,3,5-triiodobenzene or 1,3,5-tris(3',5'-diiodophenyl)benzene as the core via a simple one-pot Heck reaction and subsequent hydrolysis, phenolate formation, and heterogeneous oxidation. ESR spectra indicated a delocalized spin distribution into the core parts of the star-shaped molecules. The polyradicals, 2 and 3, were in a high-spin state at low temperature, and the ferromagnetic behavior was enhanced for the polyradical with a higher molecular weight. Although an average S of 3 remained at 3/2 to 4/2, the polyradical 2 even with a spin concentration of 0.8 spin/unit revealed an average S of 7/2 to 8/2. The 1,3,5-benzene core acted as an effective magnetic coupler to align the spins of the pendant phenoxyls through the star-shaped pi-conjugated backbone.

New functions of polymeric cobalt complexes were examined using their oxygen-binding reactions in the solid state. An oxygen-releasing device was prepared by compositing the oxygen-binding but electrically insulating cobalt-Schiff-base or -porphyrin complex with a conductive carbon powder. The device quickly released the absorbed oxygen in response to an applied voltage. A polymer film containing the cobalt-Schiff-base complex reversibly stretched in response to the atmospheric oxygen concentration. The driving force of the stretching of the film was attributed to the crystal structure change of the complex before and after the oxygen-binding.

Phospholipid vesicles encapsulating purified hemoglobin [Hb vesicles (HbV); diameter 259 +/- 82 mm; oxygen affinity 31 mm Hg; [Hb] 5 and 10 g/dL] were developed to provide oxygen-carrying capacity to plasma expanders. Their function as a blood replacement was tested in the subcutaneous microvasculature of awake hamsters during severe hemodilution in which 80% of the red blood cell mass was substituted with suspensions of the vesicles in 5% human serum albumin (HSA) solution. Vesicles were tested with membranes that were unmodified (HbV/HSA) or conjugated with polyethyleneglycol (PEG) on the vesicular surface (PEG-HbV/HSA). The viscosity of 10 g/dL HbV/HSA was 8 cP at 358 s(-1) owing to the intervesicular aggregation, while that of 10 g/dL PEG-HbV/HSA was 3.5 cP, since PEG chains inhibit aggregation. Both materials yielded normal mean arterial pressure, heart rate, and blood gas parameters at all levels of exchange, which could not be achieved with HSA alone. Subcutaneous microvascular studies showed that PEG-HbV/HSA significantly improved microhemodynamic conditions (flow rate, functional capillary density, vessel diameter, and oxygen tension) relative to unmodified HbV/HSA. Even though the enhancement of PEG modification did not achieve the functional characteristics of the blood-perfused microcirculation, PEG reduced vesicular aggregation and viscosity, improving microvascular perfusion relative to the unmodified type. These results highlight the significance of microvascular analysis in the design of red cell substitutes and the necessity of surface modification of HbV to prevent aggregation. (C) 1998 John Wiley & Sons, Inc.

Human serum albumin (HSA) incorporating synthetic tetraphenylporphinatoiron(II) derivatives (FeP1 or FeP2) can bind and release oxygen reversibly under physiological conditions (in aqueous media, pH 7.4, 37 degrees C). The maximal binding ratio of FeP1/HSA was estimated to be eight, and the stepwise equilibrium constants for FeP1 binding to HSA (K-1-K-8) ranged from 1.2x10(6) to 1.3x10(4) M-1. The major binding sites of FeP1 are presumably identical to those of hemin, bilirubin and long-chain fatty acids. The O-2-binding ability of the HSA-FeP can be regulated by changing the molecular structure of the incorporated hemes. The half-lifetime of the O-2-coordinated FeP2 in HSA was significantly longer than that of HSA-FeP1.

The oxygen-releasing behavior of hemoglobin vesicles (HbV) was measured in order to study the difference in oxygen dynamics inside and outside the cellular Hb using a conventional stopped now method and a newly developed stopped flow flash photolysis method. The partial pressure of oxygen in the solution outside the HbV was monitored with the lifetime of the triplet state of meso-tetraphenylporphinatozinc(II) bound to human serum albumin excited by the laser flash. The change in the partial pressure of oxygen outside the HbV showed a biphasic profile and was slower than that inside the HbV. The first phase shows the oxygen-releasing process from Hb near the phospholipid bilayer membrane, and the second phase is considered the process in which oxygen diffuses to the bulk aqueous region and reaches the equilibrium value.

The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to improve the oxygen carrying capability of HbV, the pH value of the Hb solution should be adjusted to 7.0 in the HbV preparation, and then the pH value should be adjusted to 7.4 where HbV functions as an oxygen carrier, because the maximum value of [Hb]/[Lipid] was obtained in which the pH of the Hb solution was 7.0, and the metHb formation rate was suppressed in the pH 7.4. Generally, the pH control of the inner aqueous phase of HbV is difficult by changing the pH in the outer phase. We could control the pH of the Hb solution from 7.4 to 7.0 by dissolving CO2 into the Hb solution, and after the preparation of HbV, the pH of HbV is changed to 7.4 by reducing the pressure. The resulting pH-controlled HbV by CO2 gas showed a high [Hb]/[Lipid] value of 1.7 with a low rate of metHb formation.

A disk (e.g. diameter 2 cm x 2 mm) was made of [N,N'-bis(salicylidene)ethylenediamine] cobalt [Co(salen)] and carbon powder. The composite disk selectively absorbed oxygen from air, e.g. 22 cm(3) oxygen per gram of composite at room temperature, which is almost stoichiometrically ascribed to 2: 1 cobalt-dioxygen adduct formation. The adduct formation was an exothermic reaction, and the absorbed oxygen was released above 80 degrees C. The application of 6 V to the disk sandwiched between platinum meshes induced a temperature elevation in the disk, which quickly released the absorbed oxygen. Under ambient conditions, the oxygen-releasing and -absorbing processes could be established within a few min and a 30 min interval, respectively, for the composite disk containing the 3-ethoxy derivative of Co(salen), while the oxygen absorption took several hours for the Co(salen) disk.

The facilitated transport of oxygen in a liquid membrane containing [meso-alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl)porphyrinatocobalt(II)]-laurylimidazole (CoP) as an oxygen carrier leads to high permeability and permselectivity of oxygen against nitrogen. The oxygen permeation was properly analyzed by a dual-mode model and using the oxygen-binding constants spectroscopically determined, to give permeation parameters of the membrane such as the diffusion coefficient (D-CoP) of the CoP mobile carrier and the physical diffusion coefficient of oxygen. D-CoP was in accordance with that electrochemically determined. The facilitated permeation was represented by the product of the Cop concentration and D-CoP in the membrane solution. D-CoP decreased with solution viscosity and increased with the measured temperature. High oxygen permeability (10(-7) cm(3)(STP) cm cm(-2) s(-1) cmHg(-1)) was observed, e.g. for the membrane of the 31 wt % CoP methylanisole solution at 10 degrees C, where the facilitation factor and the oxygen/nitrogen permselectivity were over 20 and 40, respectively.

A hydrophobic tetraphenylporphyrinatoiron(II) derivative bearing a covalently bound axial imidazole [Fe(II)P] was efficiently and noncovalently bound into human serum albumin (HSA) up to an average of eight Fe(II)P molecules per HSA molecule. The aqueous solutions of the HSA-Fe(II)P complex provided a reversible and relatively stable oxygen adduct under physiological conditions (pH 7.4 and 37 degrees C). The half-life of the oxygen adduct (tau(1/2)) was 1 h at 37 degrees C in an air atmosphere. With Fe(II)TpivPP (the so-called ''picket-fence heme'') having no axial base, an oxygenated HSA-Fe(II)TpivPP complex was obtained using a 20-fold molar excess of 1,2-dimethylimidazole, but the tau(1/2) was very short (ca. 10 min at 37 degrees C). The oxygen affinity [P-1/2(O-2)] and oxygen transporting efficiency (OTE) of HSA-Fe(II)P at 37 degrees C were 30 Torr and 22%, respectively. Furthermore, the oxygen-binding and dissociation rate constants (k(on), and K-off) are extremely high in comparison with those of hemoglobin. The HSA molecule binding eight Fe(II)P molecules can transport about 3.4 mL/dL of oxygen under physiological conditions, corresponding to about 60 % of the oxygen transporting amount of human blood.

The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to suppress metHb formation or autoxidation, for the long-term maintenance of the oxygen transporting capability, a series of thiols (cysteine, Cys; glutathione, GSH; homocysteine, Hey; and acetylcysteine, Acy) were studied as reductants of metHb. Hey and GSH showed a good suppressive effect on metHb formation, while Cys adversely accelerates the metHb formation at a rate twice that of the Ho solution without any reductants and Acy showed no change. The significant suppression by the coaddition of superoxide dismutase (SOD) and catalase to Cys indicated that Cys was easily oxidized by oxygen and simultaneously generates a large amount of active oxygens. The effective suppression of metHb formation by SOD and catalase was not observed for HbV containing no reductants, indicating that the generation of active oxygens from Hb itself is not significant. The coencapsulation of Hey with Hb resulted in a low rate of metHb formation in HbV (initial rate, 1%h) in vitro at an oxygen partial pressure (P-o2) of 142 Torr. The rate increased with decreasing P-o2, showed a maximum (2.2 %h) around P-o2 = 23 Torr, and then decreased to 0%/h at 0 Torr. From these results, it is suggested that the fast metHb formation rate in the blood circulation of Wistar rats injected with 20 vol % of the HbV solution would be mainly caused by the exposure of HbV to the low P-o2.

Encapsulation of hemoglobin within a liposome is one of the strategies in the development of artificial oxygen carriers. It maintains the oxygen transporting properties of hemoglobin and, at the same time, eliminates the side effects of cell free hemoglobin. Hemoglobin vesicles (HbV) are a type of liposome encapsulated hemoglobin. They have a particle size of approximately 250 nm, a hemoglobin concentration of 10 g/dl, and the oxygen affinity, P50, is regulated to 32 Torr. In this study the authors examined the oxygen transporting capability of HBV in vivo, by performing exchange transfusions in rats. Exchange transfusion (90% of the estimated circulatory volume) with HbV suspended in 5% albumin (containing 160 mEq/L, sodium and 107 mEq/L, chloride) was carried out in mate Wistar rats. Mean arterial pressure and heart rate were monitored through the arterial catheter. Arterial blood samples for gas analyses were also obtained from the arterial catheter. Abdominal aortic blood flow was measured by an ultrasonic pulsed Doppler flowmeter as an indicator of cardiac output. The oxygen tension of blood withdrawn from the right atrium was measured as an indicator of mixed venous oxygen tension. These values were employed to calculate oxygen delivery and consumption. Renal cortical and skeletal muscle tissue oxygen tensions were monitored as indicators of tissue perfusion. Five percent albumin and washed rat red blood cells suspended in 5% albumin containing 10 g/dl of hemoglobin, were employed as controls. At the completion of a 90% exchange transfusion, renal cortical and skeletal muscle tissue oxygen tensions, along with oxygen delivery and consumption, were sustained almost equally well with the HbV suspension compared to the washed rat red blood cell suspension, but declined significantly with the albumin suspension. The results indicate that the oxygen transporting capability of HbV was almost equivalent to that of rat red blood cells.

A polymer composite film of hemoglobin (Hb-polymer film) teas prepared by the casting of an Hb-polymer mixed solution (weight ratio of Hb to polymer is 1 to 1). The percentages of O-2 and CO saturation of the Hb-dextran film were 46% and 70%, respectively. In the Hb solution, 100% saturation was observed for both ligands, and a humidified Hb-dextran film also showed 100% saturation. Water molecules would provide flexibility to the matrix polymer and promote a structural change in the Hb from a tense state (T) to a relaxed state (R). Thus the ligand binding to the Hb in the polymer films teas strongly affected by the degree of interaction of Hb with the matrix polymers and the physical properties of the polymers. Inositol hexaphosphate (IHP) worked as an allosteric effector even in the solid polymer film and lowered the oxygen affinity of Hb. The O-2 transport through an Hb-polyethyleneimine (PEI) film with IHP showed the facilitated O-2 transport in comparison with the film without IHP because of the high dissociation rate of O-2 from Hb with IHP. (C) 1997 by John Wiley & Sons, Ltd.

The hemoglobin vesicle (HbV) has a cellular structure which encapsulates concentrated Hb in the inner aqueous phase of a phospholipid bilayer vesicle. Hb is gradually autoxidized to methemoglobin (metHb), which can not bind oxygen during oxygen transport under physiological conditions. In order to reduce metHb in HbV, we evaluated the reduction of metHb by electron transfer across the bilayer membrane of HbV from a reductant added to the outer aqueous phase. Water-soluble methylene blue (MB) and hydrophobic ubiquinone 10 (UQ) were selected as electron mediators. Under a nitrogen atmosphere, the addition of the reduced form nicotinamide-adenine dinucleotide (NADH) to the outer aqueous phase of UQ-incorporated HbV showed only a slow reduction rate for metHb. On the other hand, when MB and NADH were added under a nitrogen atmosphere to HbV containing 40% metHb, a rapid decrease in the metHb percentage was observed. The entire reaction was controlled by a reaction with NADH and MB in the outer aqueous phase. Under aerobic conditions, the decrease in the efficiency of the metHb reduction and rapid oxidation after reaching the minimal metHb percentage were observed. This was confirmed to be due to the influence of hydrogen peroxide; the decrease was prevented by the co-encapsulation of catalase.

New types of oxygen-sensitive membranes based on immobilized (meso-alpha,alpha,alpha,alpha-tetrakis(o-pivalamidopheyl) porphina-to)cobalt(II)(CoP) were prepared, and their optical response behavior was studied. The complex Cop was immobilized on poly(octylmethacrylate-co-1-vinylimidazole)(OIm) and on poly(2,2,3,3,4,4,5,5-octafluoropentylmethacrylate-co-1-vinylimidazole) (OFIm), respectively. The selective recognition mechanism for an optical response to oxygen is based on the reversible formation of oxo-adducts at the cobalt(II) centers. The useful response range was found to cover 1-1000 hPa (mbar) of oxygen partial pressure, i.e., oxygen contents of 0.1-100% at atmospheric pressure. Optimum performance was achieved with the fluorinated CoP-OFLm membrane of 20 mu m thickness, for which the 90% response time was 5-15s, and the operational lifetime was longer than 1 month.

The applicability of high-energy fast atom bombardment (FAB) collision-induced dissociation mass spectrometry/mass spectrometry (CID-MS/MS) to the structural characterization of side-chains of porphyrin derivatives with a ''tailed picketfence'' structure was examined, These porphyrins showed a molecular ion [M](+.) as well as a protonated molecule [M + H](+) and another at [M + 2](+) in the positive ion mode, Doubly-charged ions were observed when the ''tail'' has an imidazole ring,
The linked-scan spectrometry indicated that the ''tail'' of the porphyrin is eliminated first as a neutral species from the pyrrole-2-position as a beta-type cleavage, after which each of the four pivaloyl ''picket-fences'' are cleaved off in series from the remainder of the molecule-related ions, The spectrum also clearly showed charge-remote product ions in the low mass region, in addition to charge-mediated product ions representing the precise side chain structure of the ''tailed picket-fence'' porphyrin, FAB CID-MS/MS spectra of [M](+.), [M + 1](+) and [M + 2](+), using the EBEB-type four-sector tandem mass spectrometer, show similar fragmentation patterns to each other with 1 u difference in parallel, The CID-MS/MS of [M + 1](+) and [M + 2]+ showed higher product ion intensities than the corresponding product ion intensities of [M](+.), CID-MS/MS, using an EBEB-type four-sector tandem mass spectrometer, showed charge-remote product ions much more clearly than those observed in B/E-constant linked-scan spectra.

A meso-tetrakis(alpha,alpha,alpha,alpha-o-pivalamidophenyl)porphyrinatocobalt(II) derivative bearing covalently-bound imidazole (Scheme 1, CoPim) was synthesized. Oxygen-binding to CoPim was rapid and reversible. The CoPim in the solid state chemically adsorbed oxygen (20 ml O-2/g CoPim), which was ca. 40-times greater than the physical adsorption amount. The oxygen-binding lifetime of CoPim was longer than that for the corresponding porphyrinatocobalt(II) with an externally added imidazole. The efficiency of CoPim as an oxygen carrier was demonstrated by oxygen-enrichment from air using a pressure-swing adsorption experiment.

Poly(ethylene glycol) (PEG(5000))-conjugated phosphatidylethanolamine was introduced onto the surface of hemoglobin vesicles (HbV); phospholipid vesicles encapsulating concentrated Hb (d = 0.257 +/- 0.087 mu m; P-50 = 32 Torr). The obtained PEG-modified HbV (HbV-PEG) was studied for use as a red cell substitute from the viewpoint of rheology, surface properties, and hemodynamics. The viscosity of the unmodified HbV suspended in saline ([Hb] = 10 g/dL) was 2.6 cP (shear rate = 358 s(-1), 37 degrees C), less than that of human blood (4 cP). However, when suspended in a 5 g/dL albumin solution (HbV/albumin), it increased to 8 cP due to the molecular interaction between albumin and vesicles, and the viscosity increased with decreasing shear rate, e.g., 37 cP at 0.58 s(-1). As for the HbV-PEG/albumin, on the other hand, the viscosity was 3.5 cP at 358 s(-1) and was comparable with that of human blood. Optical microscopy showed formless flocculated aggregates of the unmodified HbV, while no aggregates were confirmed for the HbV-PEG. The steric hindrance of PEG chains seemed to be effective in preventing intervesicular access and the resulting aggregation To estimate the flow profiles in the capillaries, the suspensions were allowed to penetrate through isopore membrane filters (pore size = 0.4-8 mu m, cf. capillary diameter = 4-10 mu m). The penetration rate of the HbV-PEG/albumin was higher than that of the unmodified HbV/albumin due to the suppression of aggregation, whereas both of them were significantly higher than that of human blood due to the smaller size of vesicles than RBC. Ninety percent exchange transfusion was performed with the HbV-PEG/albumin or HbV/albumin in anesthetized Wistar rats (n = 6). The blood flow in the abdominal aorta increased 1.5 times, and the total peripheral resistance decreased in the HbV-PEG/albumin-administered group in comparison with the HbV/albumin group. As for the blood gas parameters, the base excess and pH remained at higher levels in the HbV-PEG/albumin group, and the O-2 tension in mixed venous blood for the HbV-PEG/albumin group tended to be maintained at a higher level than that for the HbV/albumin group. Thus, the PEG modification of HbV reduced the viscosity by the suppression of aggregation and resulted in prompt blood circulation in vivo.

The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to suppress metHb formation for the long term maintenance of oxygen transporting capability in vivo, thiols (cysteine, Cys; homocysteine, Hey) were studied as reductants of metHb. Hey showed a suppressive effect on metHb formation, while Cys adversely accelerates metHb formation at the rate of twice the Hb solution without any reductants. The suppression of Cys-induced metHb formation by the addition of superoxide dismutase (SOD) and catalase indicated that Cys was easily oxidized by oxygen and simultaneously generated a large amount of active oxygens. The rate of metHb formation was influenced by PO2 and pH. Furthermore, the reducing systems (methylene blue (MB), NADH or ascorbic acid) were added to the outer aqueous phase of HbV, and the artificial reduction systems constructed through the bilayer membrane were evaluated.

The oxygen-transporting capability of modified and encapsulated hemoglobins and red cells is discussed from a physico-chemical standpoint in order to design oxygen-delivering fluids. The oxygen diffusion coefficient toward oxygen-deficient sites was estimated by measuring the oxygen flux across thin solution membranes of hemoglobin, polymerized hemoglobin, liposome-encapsulated hemoglobin, and red cells. Oxygen flux was enhanced several times over that of nitrogen for the hemoglobin and red cell solution with cn. [Hb] = 10 and 15 g/dl, respectively. The enhancement in the oxygen diffusion is ascribed to the facilitated transport of oxygen via the hemoglobins. This was in contrast to the simple and physical oxygen-diffusivity in response to its concentration gradient, in the absence of hemoglobins. The flux of the oxygen transport was in the order of hemoglobin > red cells > polymerized hemoglobin > encapsulated hemoglobin, which was ascribed to the facilitated transport efficiencies of oxygen with hemoglobins in a non-flowing or stationary solution.

To evaluate the oxygen transporting capability of Hemoglobin vesicles (HbV) the physiological responses to 40% and 90% exchange transfusions with HbV in anesthetized rat were observed. Hb concentration of HbV dispersions is 10g/dL. HbV dispersed in phosphate buffered saline and HbV dispersed in 5% albumin solution were used as samples for 40% and 90% exchange transfusions, respectively. HbV surface-modified with polyoxyethylene (HbV-Poe) was also used in the 90% exchange transfusion. As controls, phosphate buffered saline, 5% albumin solution, and HbV containing methemoglobin and therefore deprived of oxygen transporting capabilities (metHbV) were administered as non-oxygen carrying fluids and washed rat red blood cells (ratRBC) as an oxygen carrying fluid. Measurements included mean arterial pressure, arterial blood gas analyses, aortic blood flow and renal cortical tissue oxygen tension. At the completion of the exchange transfusion renal cortical tissue oxygen tensions along with oxygen delivery and consumption were sustained almost equally well with the HbV dispersion compared to the washed rat red blood cell dispersion, but declined significantly in the phosphate buffered saline and albumin solutions. These results indicated that the oxygen transporting capability of HbV was almost equivalent to that of rat red blood cells. in the HbV-Poe group, aortic blood flow was sustained higher in comparison to the HbV group. As for the blood gas parameters, pH and venous oxygen tensions in the HbV-Poe group tended to be higher than those in the HbV group.

Objectives: To evaluate the oxygen transporting capabilities of hemoglobin vesicles by studying the physiologic responses to exchange transfusion with hemoglobin vesicles in anesthetized rats. Exchange transfusions with phosphate buffered saline, hemoglobin vesicles containing methemoglobin (and therefore, deprived of oxygen transporting capabilities), and washed rat red blood cells were used as controls.
Design: Prospective, randomized, controlled trial.
Setting: Department of Surgery, School of Medicine, Keio University.
Subjects: Twenty-seven male Wistar rats.
Interventions: The rats were anesthetized with an intraperitoneal injection of sodium pentobarbital (50 mg/kg). Catheters (PE-20 tubing, outer diameter 0.8 mm, inner diameter 0.5 mm) were introduced into the right jugular vein for infusion and the right common carotid artery for blood withdrawal and mean arterial pressure measurements. The left kidney was exposed by median abdominal incision, and a needle type polarographic oxygen electrode was placed in the left renal cortex for renal cortical tissue oxygen tension measurements.
Measurements and Main Results: Phosphate buffered saline and methemoglobin vesicles were administered as nonoxygen-carrying fluids, and rat red blood cells as oxygen carrying fluid. Measurements included mean arterial pressure, arterial blood gas analysis, and renal cortical tissue oxygen tension as an indicator of systemic oxygen transport. In the rat red blood cell and hemoglobin vesicles groups, mean arterial pressure was sustained at the end of the exchange transfusion (82.3 +/- 27.5% and 73.5 +/- 11.5%, respectively, from the basal values). However, in the phosphate buffered saline and methemoglobin vesicles groups, mean arterial pressure decreased significantly (p <.05) (33.9 +/- 13.8% and 35.7 +/- 8.2%, respectively). Renal cortical tissue oxygen tension in the rat red blood cell and hemoglobin vesicles groups was sustained at a significantly higher level (p <.05) (83.5 +/- 9.3% and 75.0 +/- 11.9%, respectively) compared with the phosphate buffered saline and methemoglobin vesicles groups (44.9 +/- 12.8% and 58.3 +/- 6.2%, respectively) at the end of the exchange transfusion. Metabolic acidosis was more progressive in the phosphate buffered saline and methemoglobin vesicles groups, manifested as lower pH and base excess values. Platelet counts tended to decrease slightly in the hemoglobin vesicles and methemoglobin vesicles groups, but the changes were not significant.
Conclusions: Hemoglobin vesicles have an oxygen transporting capability almost equivalent to rat red blood cells and can be considered as a potential artificial oxygen carrier.

The two kinds of veri cell substitutes, hemoglobin-vesicles (HbV) and lipidheme-vesicles (LihV, totally synthetic oxygen carrier), were evaluated in terms of physicochemical properties such as binding and dissociating reactions of ligands (CO, O-2 and NO), rheological and structural properties. Carbonylation of Hb during the purification of Hb and the preparation of HbV is effective to prevent Hb denaturation. The rates of oxygenation of both HbV and LihV are faster than that of I ed blood cells (RBC). Their oxygen affinities (P-50, HbV, 32 mmHg; LihV, 43 mmHg, cf. RBC, 28 mmHg) can be controlled to transport a sufficient amount of oxygen comparable with that of RBC. The smaller sizes of vesicles are advantageous for prompt ligand reaction and low viscosity. Both HbV and RBC show about 100 times less vasoconstrictive effects than stripped Hb. HbV shows only one sixth of the slow binding rate of NO (=endothelial derived relaxation factor) in comparison with stripped Hb. Inhibition of vasoconstriction by those vesicles is discussed from the kinetic data.

Oxygen permeation through solid polymer membranes is measured electrochemically by detecting the reduction current of the permeated oxygen on a carbon electrode. This method is especially effective for the measurement of facilitated oxygen transport through polymer membranes containing oxygen-specific fixed carriers, such as cobaltporphyrins, because of its high sensitivity to low permeated or downstream oxygen pressure and because it is an equal pressure process suitable for the measurement of brittle membranes with high contents of carrier molecule.

A poly mer membrane containing N'N-disalicylidenethylene-diaminocobalt (Co(salen)) was prepared. The Co(salen) supported in the polymer not only worked as a reversible and specific oxygen-adsorbent but discontinuously bound oxygen at the atmospheric oxygen partial pressure of ca. 15 cmHg to give all on-off-like oxygen-binding curve. Oxygen permeation through the Co(salen) membrane was also augmented in the higher upstream oxygen pressure region, which was caused by the specific oxygen-binding to the Co(salen) fixed in the membrane.

Poly[[2- or 4-[N-t-butyl-N-(triethylsiloxy- or t-butyldimethylsiloxy)amino]-1,4- or 1,2-phenylene]vinylene] was synthesized by polymerizing 4- or 2-bromo-2- or 4-[N-t-butyl-N- (triethylsiloxy- or t-butyldimethylsiloxy)amino] styrene with a palladium catalyst, respectively. They were deprotected and chemically oxidized to yield poly(1,4- or 1,2-phenylenevinylene)s bearing a 2- or 4-substituted built-in nitroxide radical. The polyradicals were chemically stable, and their spin concentration was increased to 0.8 spin/unit. A SQUID measurement which included the corresponding diradicals and triradicals indicated that a partial, but strong, intramolecular ferromagnetic coupling was established through the conjugated backbone, despite a spin defect in the side radical moiety, for the poly(1,2-phenylenevinylene) bearing 4-substituted built-in nitroxide radical.

A liquid membrane containing bovine hemoglobin (Hb) as an oxygen carrier was prepared, and oxygen permeation through the membrane was measured by the electrochemical reduction of the permeated oxygen. The oxygen permeation was facilitated, as analyzed by a dual-mode model, to give permeation parameters of the membranes such as the diffusion coefficient (D-Hb) Of the mobile carrier Hb and the solution-diffusion coefficient of oxygen (D-O2). The facilitated permeation was the product of the Hb concentration ([Hb](0)) and D-Hb in the membrane solution. D-Hb decreased with [Hb](0) or the solution viscosity; the maximum of the oxygen permeability (6.2 x 10(-8) cm(3)(STP)cm cm(-2)s(-1) cmHg(-1) at the feed stream oxygen pressure of 0.54 cmHg) was observed at [Hb](0) = 12.8 g dl(-1), where the facilitation factor and the oxygen/nitrogen permselectivity were ca. 10 and 18, respectively.

Hemoglobin vesicles (HbV) as red cell substitutes were prepared from a purified carbonylhemoglobin (HbCO) solution and a lipid mixture composed of phospholipids, cholesterol, and cr-tocopherol. The diameter was controlled to 251 +/- 87 nm using an extrusion method; the vesicles penetrated through the membrane filters with regulated pore sizes. After the ligand exchanging reaction (HbCO --> HbO(2)), the oxygen affinity (P-50) Of HbV was 32 Torr, which was controlled with the coencapsulation of pyridoxal 5'-phosphate. The rate of metHb formation in HbV was nonenzymatically reduced with the coencapsulation of DL-homocysteine. The Hb concentration of the HbV suspension, which was dispersed in a phosphate buffered saline solution (pH 7.4), was controlled at 10 g/dL. At this concentration, the total lipid concentration was 6.2 g/dL and the viscosity, 2.6 cP (230 s(-1)), was lower than that of the blood (4.4 cP). The HbV suspension showed a typical non-Newtonian flow for a particle dispersion and agreed well with the Casson model. The viscosity at shear rates lower than 23 s(-1) showed a maximum with increasing the mixing ratio of human blood, plasma, or albumin, while no maximum was observed for the mixture with washed red blood cells. The aggregates of HbV are formed by interaction with plasma proteins, including albumin, while the aggregates reversibly dissociate at higher shear rate.

Chemically specific surface diffusion of oxygen was observed on a porous glass membrane modified on its pore surface with cobalt porphyrin (CoP) which binds oxygen specifically and reversibly from air. The membrane displayed both permselectivity for oxygen and high permeability. The enhanced and specific diffusion of oxygen was mathematically analyzed with a parallel model involving surface diffusion of oxygen via CoP fixed on the pore surface and gas phase or Knudsen diffusion. alpha(3) beta-CoP was characterized by larger rate constants of oxygen binding (k(on)) and oxygen dissociation (k(off)), gave a larger surface diffusion constant of oxygen (D-S similar to 10(-4) cm(2) s(-1)), and brought about higher oxygen permeability through the membrane.

An amphiphilic tetraphenylporphyrinatometal (Zn, Fe) derivative having four dialkylglycerophosphocholine groups on one side of the ring plane (lipidporphyrin) was easily dispersed in an aqueous medium to give a red, stable dispersion. Based on electron microscopy, lipidporphyrins themselves produced spherical unilamellar vesicles with a diameter of ca. 100 nm. The thickness of the membrane (9.5 +/- 0.5 nm) corresponded to a bilayer of the lipidporphyrin (4.6 nm); the ratio of the lipidporphyrin molecules in the outer and inner layers was 1.57. The lipidporphyrinatozinc(II) vesicle displayed some characteristics of a J-aggregate: (i) a red-shifted Soret band (425 --> 438 nm), (ii) no fluorescence quenching, and (iii) a reduced triplet-state lifetime. Simple exciton calculations indicate that the porphyrin squares located in the outer and inner layers formed a J-aggregate with an average angle of 47 degrees. A vesicle composed of the lipidporphyrinatoiron(II) coordinated with an alkylimidazole reversibly formed a stable dioxygen adduct. The O-2-binding equilibrium and kinetic parameters were determined. This vesicle has the ability to act as a totally synthetic O-2 carrier under physiological conditions (pH 7.4, 37 degrees C).

The amphiphilic tetraphenylporphin derivative having four dialkylglycerophosphocholine groups on both sides of the ring plane (octopus-porphyrin) forms spherical monolayered vesicle membranes in water with diameters of ca, 100 nm; the vesicle constituted by octopus-porphyrinatoiron(II)/1-dodecyl-2-methylimidazole (DMIm) can reversibly bind dioxygen at 25 degrees C.

5,10,15,20-Tetrakis(o-pivalamidophenyl)porphyrins (TPVP) and their iron(II) derivatives bearing a proximal imidazole covalently bound at the 2-(beta-pyrrolic) position have been synthesized. The visible absorption maxima (lambda(max)) of the 2-substituted TPVP with an electron withdrawing group attached is shifted toward the red region (7-11 nm) compared with that of the original TPVP. The iron(II) complexes having an imidazolyl group at the beta-pyrrolic position were five coordinated species with an intramolecularly bound base under argon and reversibly formed a stable dioxygen adduct in response to O-2-pressure in toluene at 25 degrees C. These molecules act as efficient dioxygen carrying molecules. The kinetics of O-2 binding to the 2-substituted Fe(TPVP) complexes are described.

As a novel high-spin molecule, a through-bond spin-frustrated organic molecule 4, 4', 4 ''-trisdiphenylmethyleneamine (TDMA) and its anion and cation was studied by cw-ESR spectroscopy. TDMA is a spin frustrated system composed of three S=1 units coupled antiferromagnetically. This molecule was shown to have a triplet ground-state which is asymmetrical in its exchange interaction as well as its molecular conformation. The TDMA ions were generated at low temperature via successive radiolysis and photolysis of its diazo precursor. It was shown that the ground states of the anion and cation are quartet and sextet, respectively. This means that upon ionization the ground state changed from the intermediate-spin state of TDMA to the high-spin state of the ions, showing the interrelation between spin alignment and excess charge in a molecular field. On the other hand, in order to identify and discriminate the spin multiplicities of complicated spin assemblages in amorphous materials, we have developed electron spin transient nutation spectroscopy based on FT pulsed ESR and applied it to a pseudo one-dimensional high-spin polymer with effective spin S greater than or equal to 2.

Recently, organic high-spin polymers and clusters have been emerging. With the increasing effective molecular spin quantum number S and molecular weight of the polymers, however, cw ESR spectroscopy manifests its inherent disadvantages in discriminating high spins from S=1/2 and in determining the S's for the complex mixture of various spin assemblages. An electron spin transient nutation method based on pulsed ESR spectroscopy has been for the first time applied to a quasi 1D high-spin polymer as one of the most complex amorphous spin assemblages, identifying that the polymer is comprised of high-spin assemblages with the S's greater than two. It can be concluded that electron spin transient nutation spectroscopy is a facile and useful method for the exclusive identification of S and ESR transitions even for the cases of apparently vanishing fine-structure splittings and for spin systems with residual fine-structure terms in the spin Hamiltonian. Fundamental bases for the transient nutation method are described, emphasizing inherent advantages in the nutation spectroscopy from the methodological viewpoint. The salient features of multiple-quantum nutations have been disclosed in this work.

Some polymer ligands of N-vinylimidazole-co-N-vinylpyrrolidone (Plm) having different mole fractions of N-vinylpyrrolidone have been prepared. Successive formation constants for the complexation of Cu-II with these Plms in aqueous solutions have been determined by means of spectrum deconvolution at pH 3.5. The present results demonstrate that the successive formation constants are given by K-1=[CuL]/[Cu][L], K-2= [CuL(2)]/[CuL], K-3= [CuL]/[CuL(2)] and K-4 = [CuL(4)]/[CuL(3)] (charge omitted, L = imidazole residue on Plm). The results clearly indicate that the concentration ratio, [CuL] : [CuL(2)] : [CuL(3)] : [CuL(4)], is largely constant for a given Pim when the concentration of imidazole residues is varied. The values of K-2, K-3 and K-4 decrease with increasing mole fraction of vinylpyrrolidone residues (VPRo) in the Plms. The successive formation constants increase in the order K-2 < K-3 < K-4 for poly(N-vinylimidazole), whereas the reverse (i.e. K-2 > K-3 > K-4) is found for Plm with a VPRo mole fraction of 0.8. Above this VPRo mole fraction, CuL(4) species are rarely formed. These results also suggest that the distributions of Cut, species in Cu-II-Plm solutions can be controlled by adjusting the content of VPRo in the Plm.

A new homogeneous series of hydrocarbon polymers having phenoxy and thiophenoxy units in the main chain were prepared by oxidative polymerization of alpha,omega-diphenoxyalkenes (m = 2-8, 10) with S2Cl2. Polymers with weight-average molecular weights in the range of 4800-33500 have been obtained in high yields (>94%). The effect of the chain length of the methylene units on the thermal properties of the polymers is discussed. Increasing the length of the methylene units results in a decrease in the glass transition temperature (T(g)) of the polymers. An alternating odd-even effect in melting temperatures (T(m)) and molecular weights is observed. The resulting polymers having even numbers of methylene units possess a higher melting temperature and lower molecular weight than those of the odd numbered ones. Polymerization of S2Cl2 with other aromatic compounds, such as p-xylene, durene, and diphenyl ether, is also demonstrated to yield the corresponding poly(thioarylene)s. The polymerization proceeds via a cationic mechanism through the oxidation of the disulfide bond.

The electronic states of open-shell stilbene diradicals were st;hied. Previously used semiempirical MO-CI methods were applied to stilbenes having dimethylene, dioxyl, and dinitroxide centers in o,o'-, o,m'-, o,p'-, m,m'-, m,p'-, and p,p'-substitution patterns, and the various singlet-triplet energy gaps were computed to predict qualitative ground state spin multiplicities. Singlet and triplet spin states were essentially degenerate in the m,m'-isomers of disjoint connectivity, while nondisjoint o,m'- and m,p'-isomers had triplet computed ground states. Nitroxide-based diradicals showed considerably smaller computational exchange coupling energies than did other diradical models studied. As a tests of these computations, stilbenes with two N-tert-butyl nitroxide groups at the o,m'-, m,m'-, and m,p'-positions were prepared, and their magnetic properties were studied by ESR and-magnetic susceptibility measurements. The m,m'- and m,p'-isomers were found experimentally to have singlet and triplet ground states, respectively, in accord with the qualitative computed predictions.

The magnetic properties of poly(phenylacetylene)s with radical groups at the paraposition, poly[(3,5-di-tert-butyl-4-oxyphenyl)acetylene] (1),poly[[4-[(3,5-di-tert-butyl-4-oxyphenyl)(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phenyl]acetylene] (2), and poly[[4-(N-tert-butyl-N-oxyamino)phenyl]acetylene] (3), were studied with a SQUID magnetometer. The magnetization and magnetic susceptibility indicated unexpected antiferromagnetic interactions between the radical sites. The exchange interaction observed in these conjugated polyradicals was discussed in connection with their computationally modeled structures.

New derivatives of (meso-alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl)porphinato)cobalt (CoPs) were characterized by oxygen-binding equilibrium and rate constants of the cobalt centered in the porphyrins. They depended on the structure of the porphyrin; for example, the rate constants of oxygen binding and dissociation (k(on) and k(off)) for (alpha(3) beta-CoP4P (Chart 1) were 3 and 20 times as large as those for alpha(4)-CoB4P, respectively. Oxygen transport through the polymer membranes containing CoPs as the fixed oxygen carriers was facilitated and was affected by the oxygen-binding character or the structure of CoPs. The logarithmically linear correlation of the oxygen-dissociation rate constant of CoPs (k(off) = (3-66) X 10(3) s(-1)) with the diffusion constant of oxygen via CoPs fixed in the membranes (D-cc = (3-140) x 10(-9) cm(2) s(-1)) was given for those six CoP derivatives.

Poly(2,5‐dimethylphenylene sulfide) was prepared by oxidative polymerization of sulfur chloride with p‐xylene using 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ) as an oxidizing agent. The reaction proceeded efficiently under atmospheric pressure and at room temperature. The polymer formed had a high melting temperature and linear structure which was confirmed by spectroscopies. The effects of reaction time, solvent, temperature and oxidizing agent on polymerization are also discussed. Copyright © 1994 John Wiley &amp
Sons, Ltd.

Facilitated transport of oxygen in a solid Polymer membrane containing cobaltporphyrin (CoP) which carries oxygen specifically and reversibly, leads to permselectivity of oxygen against nitrogen in the membrane. The increase in concentration of the CoP carrier is expected to enhance the oxygen transport. The membranes of poly(octylmethacrylate‐co‐vinylimidazole) containing 0.8 ∼ 10 wt% CoP were prepared, and the effects of the CoP‐concentration on the transport and the diffusion constants of oxygen are studied. Although the induction period before the steady state of oxygen permeation was prolonged with the CoP concentration in the polymer membrane, the glass transition temperature (Tg) of the membrane was increased and the diffusion constants of oxygen were decreased with the CoP concentration to yield unexpected reduction of the oxygen permeation in the highly CoP loaded membrane. Copyright © 1994 John Wiley &amp
Sons, Ltd.

Oxygenated and deoxygenated hemoglobin films were obtained by drying corresponding hemoglobin solutions with maltose (≧0.3 M). The resulting hemoglobin films were homogeneous and smooth, and the methemoglobin formation in the oxyhemoglobin film was well suppressed. The dry, rigid networks of maltose molecules work to preserve the conformation of hemoglobin against the removal of water. The coordination of oxygen to the deoxygenated hemoglobin film was slow and saturated up to 50%, while nearly 100% saturation was achieved if the film contained a residual moisture of 8.7%. Copyright © 1994 John Wiley &amp
Sons, Ltd.

Poly(methacrylic acid-co-triethyleneglycol dimethacrylate) adsorbed calcium ion effectively. The adsorption obeyed Langmuir's isotherm, which indicated adsorption site [-COO-]Ca-2(2+) and its stability constant (10(4) l/mol). The resin interacted with calcium of human tooth enamel, which was adhered with the resin.

To increase the amount of oxygen transported by Hb-vesicles, it is important to suppress metHb formation. α-Tocopherol decreased lipid peroxidation in Hb-vesicles composed of EYL, whereas the Hb-vesicles composed of saturated phospholipids, such as DPPC, showed less metHb formation. To suppress metHb formation in a highly purified Hb solution, glutathione (GSH) was studied as a reductant. GSH is oxidized not only by metHb reduction but also by O₂ to generate active oxygen species, which react with Hb to form metHb. Effective nonenzymatic metHb reduction was observed at a high [Hb] because of the acceleration of metHb reduction, and at lower partial pressure of O₂ (pO₂) because of suppression of GSH oxidation. Hb-vesicles encapsulating 40g/dl Hb with pyridoxal 5'-phosphate showed high oxygen transporting efficiency. The rate of metHb formation at a low pO₂ in the blood stream was decreased by GSH.

In vivo O₂-transporting ability of totally synthetic artificial red cell (lipid-heme-microsphere) is described. O₂-Binding affinity of the lipid-heme-microsphere (P_1/2(O₂): ca. 40 Torr at 37°C) was slightly lower than that of red cell (human blood) and its O₂-association and-dissociation rate constants were larger than those of hemoglobin. O₂-Solubility of the lipid-heme-microsphere dispersion was estimated. Highly O₂-dissolved aqueous solution can be prepared by the prescription of the lipid-heme-microsphere. The totally synthetic artificial red cell suspension was intravenously injected into hemorrhagic beagles (8kg). Circulation life-time of the each constituent of this system and O₂-consumption by the lipid-heme was determined. These results suggest that the lipid-heme-microsphere has an ability to act as an efficient O₂-carrier in blood stream.

The performance of Hb-vesicles depends on the weight ratio of Hb to lipid ([Hb]/[Lipid]). This value is improved by lowering the number of bilayer membrane of the vesicle and raising the concentration of Hb in the interior of the vesicle. Maximum [Hb]/[Lipid] ratio was obtained at ca. pH 7, that would relate to the isoelectric point (pl) of Hb at 25 degrees C. On the other hand, the [Hb]/[Lipid] ratio decreased with ionic strength and increased with lowering temperature. The Hb-vesicles encapsulating 40 g/dl Hb with only one bilayer membrane were isolated by using the difference in the density of the vesicles.

A convenient method to purify Hb solution from outdated RBC has been established for the starting material of Hb-based blood substitutes. To prevent MetHb formation during the procedure, Hb in RBC was carbonylated in advance. Then RBC was mixed with organic solvent for hemolysis and centrifuged for removal of stroma. The resulting SFHb solution was heated at 60 degrees C and generated precipitates were removed out by centrifugation. The purity of Hb (25 g/dl) was confirmed by SDS-PAGE. IEF and oxygen binding property of the Kb solution also guaranteed its purity and no denaturation of Hb. This method is applicable to large scale production of the purified Hb for the starting material of Hb-based blood substitutes.

Triglyceride microsphere emulsified with phospholipid derivative of heme (5,10,15,20-tetrakis[alpha,alpha,alpha,alpha-o-[2,2-dimethyl-20-[2-(trimethylammonioethoxy) phosphonatoxy]eicosanamido]phenyl]porphinatoiron(II); lipidheme) provides a totally synthetic artificial red cell (lipidheme-microsphere; LH-M). Its structure, solution properties and O-2, binding ability are described. The particle diameter of the LH-M was ca. 90 nm phi elucidated by electron microscopy. Viscosity of the LH-M suspension (similar to 1.5 cP) was much lower than that of human blood and the viscosity of mixed system of LH-M/human blood (1/1(v/v)) was 2.5 cP. Specific gravity, osmotic pressure, and colloid osmotic pressure of the LH-M suspension also satisfied the physiological needs. The LH-M can bind O-2 reversibly in response to O-2 pressure (P-50(O-2): 41 torr (pH 7.4, 37 degrees C)). O-2 solubility of the LH-M was more than that of human blood caused by its high heme concentration.

We have succeeded in synthesizing a new type of totally artificial oxygen carrier which was produced by covering oil droplets (microsphere) with synthetic hemes (LH-M). We studied its oxygen-transporting ability in hemorrhagic dogs.
Four beagles weighing about 8 kg were studied. Under controlled ventilation, exchange-transfusion of 30 ml/kg was carried out. Cardiac output, hemoglobin and LH-M concentration in the blood, and blood gas were measured to 5 hours after intravenous injection of LK-M solution.
LH-M delivered 15.7 to 22.3 ml/min (11 to 16 %) of oxygen to the tissue and 5.5 to 8.2 ml/min (11 to 17 %) of oxygen was consumed from LH-M to 5 hours after intravenous injection. Its half-life time in the blood stream was about 12 hours. It was confirmed that LK-M transported oxygen and released it to the tissue in vivo.

Protoporphyrin IX derivatives having two alkylphosphocholine groups (lipid-porphyrins) forms stable fibrous aggregates in aqueous medium; fibres have been spontaneously incorporated into the bilayer of the phospholipid vesicle.

[4-(N-tert-Butyl-N-hydroxyamino)phenyllacetylene (7) was synthesized and polymerized to yield a solvent-soluble polyacetylene: poly[[4-(N-tert-butyl-N-hydroxyamino)phenyl]acetylene] (8). Oxidation of the polymer gave its radical derivative: the ESR spectrum showed a broad signal only in the DELTAm(s) = +/-1 region, and magnetic measurement with a SQUID magnetometer revealed an antiferromagnetic through-space interaction.

Double-sided porphyrinatoiron(II) complexes bearing covalently bound axial imidazole, 5-[2-(5-imidazolylvaleryloxy)-6-(pivaloyloxy)phenyl]-10,15,20-tris[2,6-bis(pivaloyloxy)phenyl]porphyrinato-iron(II) and 5-[2-(3,3-dimethylbutyryloxy)-6-(5-imidazolylvaleryloxy)phenyl]-10,15,20-tris[2,6-bis(3,3-dimethylbutyryloxy)phenyl]porphyrinatoiron(II), have been synthesized. On the basis of their absorption and H-1 NMR spectra, the axial imidazole group is co-ordinated. The complexes reversibly form stable dioxygen adducts in toluene at 25-degrees-C, and the kinetics of binding of 02 and CO has been investigated. When embedded in phospholipid unilamellar vesicles, the complexes possess the ability to transport dioxygen in an aqueous medium. The binding affinity of the pivaloyloxy derivative [P1/2(O2) = 27 Torr] is equal to that of a red blood cell suspension and the half-life of the dioxygen adduct formed was 1.5 d under physiological conditions (pH 7.4, 37-degrees-C).

Oligo(p-phenylene sulfide) is synthesized through oxygen oxidative polymerization of diphenyl disulfide catalyzed by vanadyl acetylacetonate. The mechanistic studies reveal that two redox cycles [V(M)/V(IV) and V(IV)/V(V)] give rise to catalysis through a 2-electron transfer between diphenyl disulfide and molecular oxygen. The VO catalysts act as an excellent electron mediator to bridge a 1.0-V potential gap between the oxidation potential of disulfides and the reduction potential of oxygen. The VO-catalyzed oxygen oxidative polymerization provides pure oligo(p-phenylene sulfide)s containing an S-S bond. The polymeric product is of low molecular weight due to the insolubility of poly(p-phenylene sulfide) under these experimental conditions.

Amphilphilic tetraphenylporphin derivatives having four dialkylglycerophosphocholine groups on the ring plane (lipid-porphyrins) form spherical unilamellar vesicles of diameter ca. 100 nm in water; the vesicles composed of lipid-porphyrinatoiron(II)-1-dodecylimidazole (DIm), can bind dioxygen reversibly in aqueous medium.

Amphiphilic tetraphenylporphyrins having four alkyl phosphocholine groups on each side of the ring plane (octopus-porphyrins) form fibrous aggregates in dilute aqueous solution; the vesicles, constituted by iron(II) derivative-1-dodecyl-2-methylimidazole (DMIm), have the ability to bind dioxygen reversibly in aqueous medium.

Synthesis and characterization of two amphiphilic tetraphenylporphinatoiron complexes having a glycerophosphocholine or an alkyl phosphoserine group are described. These porphinatoiron(II) complexes with 1-dodecyl-2-methyl-imidazole (L2MIm) were efficiently embedded in the bilayer of a phospholipid vesicle due to their high compatibility with lipids, similar to the heme substituted with four alkyl amphiphilic chains (lipid-heme). Oxygen transporting ability of the phospholipid vesicles embedded with hemes were similar to that of hemoglobin (Hb) in red blood cells.

Photoreaction of camphorquinone (CQ) and dimethylaminoethyl methacrylate (DMAEMA) and its initiation capability of MMA polymerization was studied as a model system for visible light-cured dental composite resins. The photo-sensitizer (CQ) produced CQ radical anion by irradiation in the presence of the reducing agent (DMAEMA) under N2. ESR signal intensity and the IR and UV-Vis absorption spectra of CQ carbonyl group decreased during irradiation, and the polymerization rate of MMA depended on the decrease in the CQ carbonyl group. The hydrogen abstraction reaction by CQ radical seemed to promote the polymerization of MMA. Atmospheric oxygen inactivated the CQ radical and reduced the polymerization.

The quality of artificial red cells (ARC); Hb-vesicles (200nmφ), can be evaluated from the lamellarity (n) of Hb-vesicles and the concentration of Hb in lipid membrane vesicles ([Hb]_in) as well as oxygen binding properties of Hb vesicles. It is important to prepare Hb-vesicles with higher concentration of Hb ([Hb]_in) and lower lamellarity (n). [Hb]_in increased with the concentration of Hb used for the preparation of Hb-vesicles. The Hb-vesicles with smaller lamellarity could be obtained with lowering the preparation temperature. Covering of lipid membrane to the concentrated Hb solution was also influenced by the ionic strength and the pH of the Hb solution because lipids and Hb are electrolytes. The highest [Hb]/[Lipid] ratio was obtained when the pH was at around isoelectric point of Hb (pI=7.0). The lamellarity decreased with decreasing the concentration of NaCl.

Solution properties and O₂ transporting ability of lipidheme-microsphere composed of oil droplet covered with lipidheme (totally synthetic artificial red cell) are described. Electron micrographs indicated microsphere formation and its particle diameter was controlled from 30 to 200nm. The suspension was characterized by its low viscosity (1, 2cP), specific gravity (1.001), and controlled oncotic pressure. The lipidheme-microsphere bound oxygen reversibly and the P_1/2(O₂) was 41 torr at 37°C. O₂ solubility of the lipidheme-microsphere was more than that of human blood caused by its high heme concentration. Exchange transfusion with the suspension to dogs weighing ca. 8kg was carried out and circulation half life in blood stream was determined (12hr). This result suggests that the lipidheme-microsphere has potential to act as an efficient oxygen carrier in blood stream.

Diphenyl disulfides yield oligo(p-phenylene sulfides) by an anodic oxidation in dichloromethane solution in the presence of protonic acids such as trifluoroacetic acid. The acid suppresses the nucleophilic reaction of the cationic active species and the electro-oligomerization of diphenyl disulfide proceeds through an electrophilic reaction of a cation formed anodic oxidation. The oxidation of diphenyl disulfide proceeds through a one-electron transfer and via phenyl-bis(phenylthio) sulfonium cation as an active species in this oligomerization, which was confirmed electrochemically. Upon adding benzoquinones and cerium acetylacetonate to the mixture, the oligomerization proceeds efficiently to give a high yield of the oligomer and can be carried out at a lower applied potential (1.7 to 0.8 V vs. Ag/AgCl).

[4-[(3,5-Di-tert-butyl-4-hydroxyphenyl)(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phenyl]acetylene (6), was synthesized and polymerized to yield a solvent-soluble polyacetylene poly[[4-[(3,5-di-tert-butyl-4-hydroxyphenyl)(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phenyl]acetylene] (5a). The polymer gave its polyradical derivative 5b through the chemical oxidation with active PbO2. 5b was stable, whose spin concentration could be increased up to 4.8 x 10(23) spins per molar monomer unit. ESR analysis indicated localization of unpaired electrons in the galvinoxyl residue. ESR analysis also suggested an exchange-narrowing and interpolymer dipole-dipole interaction.

Lipophilic heme (1-laurylimidazole-ligated 5,10,15,20-tetrakis(alpha,alpha,alpha,alpha-omicron-pivalamidophenyl)porphinatoiron(II) complex) is solubilized in lipid (triglyceride) at high concentrations and emulsified with a phospholipid in physiological salt solution, giving a deeply red-colored suspension of lipid microspheres (approx. 250 nm in diameter). The heme forms an oxygen adduct in a similar manner as oxyhemoglobin and the lipid microspheres take up and release oxygen reversibly at 37-degrees-C in the aqueous medium. The oxygen-transporting ability is comparable with that of the red blood cell. Intravenous injection of thc heme/lipid microsphere solution to rabbits demonstrates that it transports oxygen even in vivo and that it is cleared from the blood stream with a half-life time of approx. 1 h.

Alkyl-substituted poly(arylene sulfide)s (PASs) are prepared by the oxidative polymerization of diaryl disulfides with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The structures of the formed poly(arylene sulfide)s are confirmed by spectroscopic measurements. The linear structure of poly(2-methyl-1,4-phenylene sulfide) is confirmed by comparing its spectroscopic data with those of the polymer prepared from bis(2-methylphenyl) disulfide, bis(3-methylphenyl) disulfide and (4-bromo-2-methylthiophenoxy) copper salt. Bis(2,5-dimethylphenyl) disulfide is easily polymerized to poly(2,5-dimethyl-1,4-phenylene sulfide) with high yield and high melting point in comparison with the other methyl-substituted poly(arylene sulfide)s, due to the symmetry of the polymer structure. The polymerization reaction, with the exception of bis(3,5-dimethylphenyl) disulfide, produces low molecular weight polymers because of the solvent insolubility of PASs and the low reactivity of diaryl disulfides. Soluble poly(2,6-dimethylphenylene sulfide) is isolated by the polymerization of bis(3,5-dimethylphenyl) disulfide as a white powder with ca. 3 x 10(4) weight-average molecular weight.

3,5-Dimethylthiophenol and bis(3,5-dimethylphenyl) disulphide have been electro-oxidatively polymerized to poly(2,6-dimethylphenylene sulphide) under mild conditions. The polymer film formed on the electrode has a semi-conductivity of 10(-9) S/cm and electrochemical response. Its redox potential at 1.3 V corresponds to a doping-dedoping reaction.

Luminescence properties of Tb3+ - or Eu3+ -polycarboxylate complexes in aqueous solution were investigated. The excitation bands near 300 nm for terbium- or europium-polyacrylate solutions were drastically enhanced by the addition of hydroxyl-radical generating reagents as well as ultrasonic irradiation. These spectral changes were attributed to the energy transfer from chromophore molecules found by the hydroxyl radicals generated in both systems.

(3,5-Di-tert-butyl-4-hydroxyphenyl)acetylene (8) was synthesized and polymerized with WCl6 and MoCl5, giving a novel and solvent-soluble conjugated polymer, poly[(3,5-di-tert-butyl-4-hydroxyphenyl)-acetylene] (3). Visible absorption of the polymer indicated a fairly long pi-conjugated system along the main chain. The polymer yielded its polyanion 10 and polyradical derivative 4 after the treatment of its solution with an alkali and oxidizing reagent, respectively. The polyradical 4 was surprisingly stable, and spin concentration was increased up to 2.3 x 10(22) spins/molar (hydroxyphenyl)acetylene residue. ESR spectra of the polyradical 4 in solution suggested that the formed upaired electrons were delocalized along the polyacetylene main chain. 4 was also very stable even in solid state. Spin-exchange interaction observed in 4 strongly depended on its spin concentration. Antiferromagnetic interaction between the upaired electrons was suggested from the temperature dependency of the ESR signal intensity.

The polymerization behavior of acrylic monomers in the light-cured composite resins and the stability of residual radicals were investigated. The monomer conversion and radical concentration were determined by ESR and IR spectroscopies under various conditions. Slow polymerization proceeded even in the dark by residual radicals, which served post curing of the resins. A decrease in monomer consumption was observed at the surface due to an inhibition effect of oxygen on the photoinitiation process.

The combination membrane of poly(1-trimethylsilyl-1-propyne) with enormously high permeability and poly(vinylimidazole)-bound porphinatocobalt with selective oxygen-binding ability was prepared. Oxygen transport through the membrane was facilitated in terms of oxygen transport via the latter domain as a fixed oxygen-carrier, and this oxygen permeability maintained for a month.

In vivo oxygen transporting capacity of totally synthetic artificial red cell (poly-liposome embedded lipid-heme) solution, which can bind and release molecular oxygen under physiological condition, was described. Exchange transfusion with the lipid-heme solution to six dogs weighing about 8kg was carried out. After the transfusion with 30ml/kg of the lipid-heme solution, the oxygen partial pressure of mixed venous blood increased from 30 to 50mmHg. Oxygen consumption by the lipid-heme was calculated to be 15ml/min (20% of total oxygen transport), which is corresponding to the lipid-heme concentration in the blood stream. Circulation half-life time in the blood stream was about 11hr. for the lipid-heme and about 26hr. for the liposome. Oxidation rate of the lipid-heme (met-formation) in the blood stream was slower than that of in vitro: only 6% of the lipid-heme was oxidized at 11hr. after the injection.

Polymerized phospholipid vesicle encapsulating Hb (polylipid/Hb vesicle) was prepared from a mixture of unsaturated phospholipid, cholesterol and unsaturated fatty acid and polymerization by gamma-ray irradiation. The average radius of resulting vesicles was 203 +/- 39 nm and concentrated Hb (30 wt%) was efficiently encapsulated. gamma-Ray polymerization proceeds theoretically at low temperature (4-degrees-C). P50 and oxygen transporting efficiency were adjusted to 40 mmHg and 40%, respectively. Oncotic pressure and solution viscosity can be controlled to the same values as blood.

The kinetics of binding of O2 and CO to double-sided porphyrinatoiron(II) complexes having ester pockets on both sides of the porphyrin plane has been studied. The specific environment created by the four ester groups around the central iron(II) ion of 5,10,15,20-tetrakis(2,6-di-tert-butylacetoxyphenyl)-porphyrinatoiron(II) 2 results in binding which is not affected by solvation. The lower binding affinity for CO of 5,10,15,20-tetrakis(2,6-dipivaloyloxyphenyl)porphyrinatoiron(II) 1 compared to that of 5,10,15,20-tetra (o-pivalamidophenyl)porphyrinatoiron(II) is attributed to the unfavourable steric repulsions between the axial imidazole ligand and the pivaloyloxy groups, and is reflected in decreased association and increased dissociation rates. On the other hand, axial base ligation to 2 is not inhibited by the tert-butylacetoxy groups. Therefore, the lower binding affinity for O2 exhibited by 2 compared to that of an amide fenced porphyrin complex is ascribed to the loss of local polarity in the cavity. The less-polar ester groups of the double-sided porphyrinatoiron complex result in an increased rate of dissociation of O2. The activation energy for gaseous ligand association to complex 2 was determined.

Metal-ligand bonding properties of double-sided porphyrinato-iron(II) and -cobalt(II) complexes have been characterized by ESR, IR, and Mossbauer spectroscopy. The smaller A(N) value for a 1-methylimidazole (mim) adduct of 5,10,15,20-tetra(2,6-dipivaloyloxyphenyl)porphyrinatocobalt(II) compared to that of 5,10,15,20-tetra(2,6-di-tert-butylacetoxyphenyl)porphyrinatocobalt(II) suggested that the cobalt-imidazole bond is weak. The ESR spectrum of the dioxygenated double-sided series in fluid toluene indicated that an electrostatic interaction between the bound dioxygen and the ester fences was rarely found. The relaxation of steric strain on the rear side of the ring plane for axial imidazole bonding resulted in a lowering of the bound CO and O2 stretching frequencies of iron(II) complexes. This indicates that the pi-back donation from the d-pi orbital of the iron to the pi* orbital of the bound gaseous ligand could be controlled by the strength of the iron-imidazole bonding, which is regulated by the structure of the rear pocket on the macrocycle. The co-ordination structure of various ligands in double-sided porphyrinatoiron complexes is also discussed by means of Mossbauer parameters.

Specific and facilitated transport of molecular oxygen through a polymer membrane containing [alpha-mono(o-methacrylamidophenyl)-alpha,alpha,alpha-tris(o-pivalamidophenyl)porphinato]cobalt (CoMPP) complex as a fixed oxygen carrier is analyzed by a modified dual-mode transport theory, and the effect of the polymer matrix on the oxygen diffusion via the fixed carrier is discussed. Oxygen diffusion coefficients for the diffusion from the polymer matrix to the fixed carrier (D(DC)) and for the diffusion from the fixed carrier to the polymer matrix (D(CD)) increase with physical diffusivity through the polymer matrix. In contrast, the oxygen diffusion coefficient for hopping between the fixed carriers (D(CC)) is independent of the polymer matrix species.

Selective sorption and permeation of molecular oxygen are described for meso-alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl)porphinatocobalt(II) (CoP) coordinated polymer membranes (Chart I). Oxygen solubility is ca. 70 times augmented in comparison with that of nitrogen by the CoP loading in the membrane. Sorption isotherms of oxygen for the membranes are analyzed with a dual-mode sorption model to give C(c)' and K. C(c)' (the saturated amount of oxygen reversibly bound to the CoP sorption site) is independent of temperature and increases with the loaded CoP amount into the membrane. K (the oxygen-affinity constant of CoP) agrees with that determined spectroscopically by monitoring the CoP moiety in the membrane. Oxygen permeation through the membrane is facilitated, and the permeability is in accordance with a dual-mode transport model. Substituting the sorption parameters, C(c)' and K, in the model yields diffusion constants of oxygen in the membranes.

A copolymer of (vinylcyclopentadienyl)dicarbonylmanganese (CpMn) an octyl methacrylate forms its acetylene-coordinated complex reversibly and stably in the solvent-free membrane state. Kinetic and equilibrium constants of the acetylene coordination to the CpMn residue in the copolymer membrane are determined spectroscopically in situ. The acetylene coordination parameters are much smaller than those of the corresponding nitrogen coordination. Acetylene transport for the membrane is expected to be selectively augmented due to the coordination of acetylene to the fixed CpMn. However, acetylene transport behavior is in accordance with total immobilization of acetylene on the CpMn residue in the acetylene permeation through the membrane.

Poly(thioarylene)s are conveniently prepared in high yield at room temperature and atmospheric pressure through oxidative and electrophilic reaction of disulphur dichloride (S2Cl2) and aromatic compounds.

Polyaromatic sulfides are efficiently and conveniently prepared by cationic oxidative polymerization. Diphenyl disulfides are quantitatively polymerized to yield poly(p-phenylene sulfide)s as white powders whose structure predominately contains 1,4-phenylene sulfide bonds. The disulfides are oxidized to phenylbis(phenylthio) sulfonium cations as active species of the polymerization. Repeating the oxidation and electrophilic reaction of the cation to the p-position of disulfides yields the polymer.

Synthesis and magnetic properties of pi-conjugated stable polyradicals bearing a polyacetylene backbone are described. 2,6-Di-tert-butyl-4-ethynylphenol (8) and 4-ethynylphenylhydrogalvinoxyl (9) are polymerized with W, Mo chloride or Rh complex to yield their polyacetylene derivatives with molecular weight of ca. 10(4), while 2-ethynylphenalenone (10) gives only its oligomer. The polymers are soluble in common solvents and converted to the corresponding conjugated polyradicals via heterogeneous chemical oxidation using PbO2 or alkaline K3Fe(CN)6. The polyradicals with extremely high spin concentration (up to 4.8 x 10(23) spins/monomer mol) are obtained by regulating the oxidative conditions. The polyradicals are quite stable in solution and even in the solid state because of resonance stabilization and/or a steric effect of the substituents. Magnetic interactions between the unpaired spins in the conjugated stable polyradicals are discussed.

Poly(p-phenylenesulfide) (PPS) is efficiently and conveniently produced by a cationic and oxidative polymerization. Diphenyldisulfide is polymerized to PPS through one electron transfer at room temperature. The polymer is isolated as a white powder whose 1,4-structure is confirmed by IR. Phenylbis(phenylthio)sulfonium ion acts as an active species which is formed by oxidation of the S-S bond of diphenyldisulfide, and electrophilically substitutes on the phenyl ring. This polymerization is applicable to the polymerization of alkyl-substituted diphenyldisulfides to give PPSs, such as poly(2-methylphenylenesulfide) and poly(3,5-dimethylphenylenesulfide).

Formation and magnetic properties of pi-conjugated phenoxy radicals bearing a porphyrin macrocycle or a polyacetylenic backbone are described. Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphinatometals (7-M) [M = Zn(II), VO(II), and Cu(II)] were oxidized to give the corresponding stable monoradical and biradical. Magnetic properties of the radical species depend on the magnetic orbital of the central metal ion. ESR hfs structure reveals that the biradical for 7-Zn and - VO are in the triplet (S = 1) and quartet state (S = 3/2), respectively. Poly(3,5-di-t-butyl-4-hydroxphenylacetylene) (8) and poly(p-ethynylphenylhydrogalvinoxyl) (9) with molecular weights of similar-to 10(4) are characterized. ESR spectra with hyperfine structure for 8 indicate that the phenoxy radicals are conjugated with the polyacetylenic main chain over similar-to 7 monomer units as a "neutral soliton." Formed polyradicals for 8 and 9 are surprisingly stable, even in the solid state, due to resonance stabilization and/or steric effect of the conjugated main chain. An antiferromagnetic interaction is observed for oxidized 8 with a spin concentration above 10 mol%.

Lipid-heme solution transports molecular oxygen under physiological condition. A rabbit was connected with a respirator and was ventilated with 10% oxygen (F_Io₂=0.1). Oxygen saturation (So₂) and oxygen partial pressure (Po₂) of the venous blood were measured. When the rabbit was ventilated at F_Io₂=0.1, Svo₂ was reduced to 20%. The infusion of the lipid-heme solution saturated with oxygen into the abdominal cavity enhanced Svo₂ up to 60%.<br>Exchange-transfusion of the lipid-heme solution to a dog was carried out with the rate of 10ml/min. Po₂ of the mixed venous increased from 30 to 44mmHg after the transfusion of the lipid-heme solution. The total blood flow (cardiac output) was 0.73l/min. The oxygen delivering amount or consumption (Vo₂) of the lipid-heme solution and of blood were calculated to be 9.2 and 50ml/min, respectively, which were corresponding to the intravascular concentrations of the lipid-heme and the red blood cell. Oxygen transporting ability of the lipid-heme solution was discussed.

5,10,15,2O-Tetra(01,01,01,01-0-(2,' 2'-dimethyl-20'-(2”-trimethylarnmonioethyl) phosphonatoxyeicosanamido)phenyl)porphinatoiron(II) (lipidheme) complex embedded in polymerized liposome was prepared by polymerizing 1-(9-(p-vinylbenzoyl)nonanoyl)-2-O-octadecyl-ruc-glycero- 3-phosphocholine in the presence of lipid-heme under ultraviolet irradiation. The polymerization proceeded rapidly, and the reduction of the hemin to the heme occurred spontaneously during the polymerization. The lipid-heme complex embedded in the polymerized liposome bound molecular oxygen reversibly under physiological conditions (pH 7, 37ºC) and was chemically, physically, and mechanically stable during storage for a long period and even in a high-speed flow system. The oxygenbinding affinity was not affected by the type of medium due to the effect of the rigid polymerized liposome. © 1987, Taylor &amp
Francis Group, LLC. All rights reserved.