2022/12/09 更新

写真a

オカザワ アツシ
岡澤 厚
Scopus 論文情報  
論文数: 0  Citation: 0  h-index: 16

Citation Countは当該年に発表した論文の被引用数

所属
理工学術院 先進理工学部
職名
講師(任期付)

学歴

  • 2006年04月
    -
    2009年03月

    電気通信大学   大学院電気通信学研究科   量子・物質工学専攻 博士後期課程  

  • 2004年04月
    -
    2006年03月

    電気通信大学   大学院電気通信学研究科   量子・物質工学専攻 博士前期課程  

  • 2000年04月
    -
    2004年03月

    電気通信大学   電気通信学部   量子・物質工学科  

学位

  • 電気通信大学   博士(理学)

  • 電気通信大学   修士(工学)

  • 電気通信大学   学士(工学)

経歴

  • 2022年04月
    -
    継続中

    早稲田大学   先進理工学部 電気・情報生命工学科   講師

  • 2020年04月
    -
    2022年03月

    日本大学   医学部 一般教育学系化学分野   助教

  • 2009年08月
    -
    2020年03月

    東京大学 大学院総合文化研究科   助教

  • 2009年04月
    -
    2009年08月

    日本学術振興会   特別研究員(PD)

  • 2008年04月
    -
    2009年03月

    独立行政法人日本学術振興会

  • 2008年04月
    -
    2009年03月

    日本学術振興会   特別研究員(DC2)

▼全件表示

所属学協会

  •  
     
     

    メスバウアー分光研究会

  •  
     
     

    電子スピンサイエンス学会

  •  
     
     

    分子科学会

  •  
     
     

    錯体化学会

  •  
     
     

    日本化学会

  •  
     
     

    アメリカ化学会

▼全件表示

 

研究分野

  • 機能物性化学

  • 無機・錯体化学

研究キーワード

  • レドックスフロー電池

  • メスバウアー分光

  • 有機ラジカル

  • 有機無機複合体

  • 分子性磁性体

  • 単分子磁石

  • 有機・錯体物性化学

  • Single-molecule magnets

  • Molecule-based magnets

▼全件表示

論文

  • Photoinduced Persistent Polarization Change in a Spin Transition Crystal.

    Sheng-Qun Su, Shu-Qi Wu, Yu-Bo Huang, Wen-Huang Xu, Kai-Ge Gao, Atsushi Okazawa, Hajime Okajima, Akira Sakamoto, Shinji Kanegawa, Osamu Sato

    Angewandte Chemie (International ed. in English)     e202208771  2022年07月  [国際誌]

     概要を見る

    Using light as a local heat source to induce a temporary pyroelectric current is widely recognized as an effective way to control the polarization of crystalline materials. In contrast, harnessing light directly to modulate the polarization of a crystal via excitation of the electronic bands remains less explored. In this study, we report an FeII spin crossover crystal that exhibits photoinduced macroscopic polarization change upon excitation by green light. When the excited crystal relaxes to the ground state, the corresponding pyroelectric current can be detected. An analysis of the structures, magnetic properties and the Mössbauer and infrared spectra of the complex, supported by calculations, revealed that the polarization change is dictated by the directional relative movement of ions during the spin transition process. The spin transition and polarization change occur simultaneously in response to light stimulus, which demonstrates the enormous potential of polar spin crossover systems in the field of optoelectronic materials.

    DOI PubMed

    Scopus

  • Manipulating electron redistribution to achieve electronic pyroelectricity in molecular [FeCo] crystals.

    Pritam Sadhukhan, Shu-Qi Wu, Jeremy Ian Long, Takumi Nakanishi, Shinji Kanegawa, Kaige Gao, Kaoru Yamamoto, Hajime Okajima, Akira Sakamoto, Michael L Baker, Thomas Kroll, Dimosthenis Sokaras, Atsushi Okazawa, Norimichi Kojima, Yoshihito Shiota, Kazunari Yoshizawa, Osamu Sato

    Nature communications   12 ( 1 ) 4836 - 4836  2021年08月  [国際誌]

     概要を見る

    Pyroelectricity plays a crucial role in modern sensors and energy conversion devices. However, obtaining materials with large and nearly constant pyroelectric coefficients over a wide temperature range for practical uses remains a formidable challenge. Attempting to discover a solution to this obstacle, we combined molecular design of labile electronic structure with the crystal engineering of the molecular orientation in lattice. This combination results in electronic pyroelectricity of purely molecular origin. Here, we report a polar crystal of an [FeCo] dinuclear complex exhibiting a peculiar pyroelectric behavior (a substantial sharp pyroelectric current peak and an unusual continuous pyroelectric current at higher temperatures) which is caused by a combination of Fe spin crossover (SCO) and electron transfer between the high-spin Fe ion and redox-active ligand, namely valence tautomerism (VT). As a result, temperature dependence of the pyroelectric behavior reported here is opposite from conventional ferroelectrics and originates from a transition between three distinct electronic structures. The obtained pyroelectric coefficient is comparable to that of polyvinylidene difluoride at room temperature.

    DOI PubMed

    Scopus

    9
    被引用数
    (Scopus)
  • Transparent Ion-Exchange Membrane Exhibiting Intense Emission under a Specific pH Condition Based on Polypyridyl Ruthenium(II) Complex with Two Imidazophenanthroline Groups.

    Hajime Kamebuchi, Satoshi Tamaki, Atsushi Okazawa, Norimichi Kojima

    Membranes   11 ( 6 )  2021年05月  [国際誌]

     概要を見る

    The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2'-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s-1 and knr = 7.03 × 105 s-1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent "off-on-off" emission behavior.

    DOI PubMed

    Scopus

  • Triplet Excited States Modulated by Push–Pull Substituents in Monocyclometalated Iridium(III) Photosensitizers

    Shin-ya Takizawa, Sora Katoh, Atsushi Okazawa, Naoya Ikuta, Satoko Matsushima, Fanyang Zeng, Shigeru Murata

    Inorganic Chemistry    2021年03月

    DOI

    Scopus

    5
    被引用数
    (Scopus)
  • Molecular Magnetism of Metal Complexes and Light-Induced Phase Transitions

    Norimichi Kojima, Atsushi Okazawa

    MODERN MOSSBAUER SPECTROSCOPY: NEW CHALLENGES BASED ON CUTTING-EDGE TECHNIQUES   137   267 - 317  2021年

     概要を見る

    One of the most attractive research in the field of molecular solids is multifunctional molecular magnets coupled with spin, charge and photon, and single-molecular magnet/single-chain magnet toward spintronics. In this chapter, we focus on the molecular magnetism and its related light-induced phase transitions from the viewpoint of Mossbauer spectroscopy. In the Sect. 6.1, the outline of this chapter is described. In the Sect. 6.2, static and dynamic spin crossover phenomena between the high-spin and low-spin states, and the spin frustration system induced by dynamic spin crossover phenomena for [MnIIFeIII(C2O3S)(3)] complex are described. In the Sect. 6.3, metal complexes showing charge transfer phase transitions such as Prussian blue analogous complexes and [FeIIFeIII(C2O2S2)(3)] complexes and their photoinduced phase transitions are described. In the Sect. 6.4, various kinds of molecular magnets including single molecular chain magnets are described.

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Three‐Step Spin State Transition and Hysteretic Proton Transfer in the Crystal of an Iron(II) Hydrazone Complex

    Takumi Nakanishi, Yuta Hori, Shuqi Wu, Hiroyasu Sato, Atsushi Okazawa, Norimichi Kojima, Yusuke Horie, Hajime Okajima, Akira Sakamoto, Yoshihito Shiota, Kazunari Yoshizawa, Osamu Sato

    Angewandte Chemie International Edition   59 ( 35 ) 14781 - 14787  2020年08月  [査読有り]

     概要を見る

    A proton-electron coupling system, exhibiting unique bistability or multistability of the protonated state, is an attractive target for developing new switchable materials based on proton dynamics. Herein, we present an iron(II) hydrazone crystalline compound, which displays the stepwise transition and bistability of proton transfer at the crystal level. These phenomena are realized through the coupling with spin transition. Although the multi-step transition with hysteresis has been observed in various systems, the corresponding behavior of proton transfer has not been reported in crystalline systems; thus, the described iron(II) complex is the first example. Furthermore, because proton transfer occurs only in one of the two ligands and yr electrons redistribute in it, the dipole moment of the iron(II) complexes changes with the proton transfer, wherein the total dipole moment in the crystal was canceled out owing to the antiferroelectric-like arrangement.

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Multicolor Emission and Photophysical Properties of Proton-Responsive Cyclometallated Iridium(III) Complex in Transparent Cation-Exchange Membrane

    Hajime Kamebuchi, Yu Fujimura, Taiho Yoshioka, Atsushi Okazawa, Makoto Tadokoro, Norimichi Kojima

    Crystals   10 ( 8 ) 653 - 653  2020年07月

    DOI

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    1
    被引用数
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  • In-beam Mossbauer spectra for Mn-57 implanted sulfur hexafluoride

    Yasuhiro Yamada, Yukiko Sato, Yoshio Kobayashi, Takatoshi Ando, Noriko Takahama, Kanako Some, Masami Sato, Mototugu Mihara, M. Kenya Kubo, Wataru Sato, Jun Miyazaki, Takashi Nagatomo, Junji Kobayashi, Atsushi Okazawa, Shinji Sato, Atsushi Kitagawa

    HYPERFINE INTERACTIONS   241 ( 1 )  2020年02月

     概要を見る

    To investigate the interactions of Fe-57 atoms with sulfur hexafluoride SF6 molecules, in-beam Mossbauer spectra were measured for Mn-57 implanted SF6 at 9 K and 65 K. Isolated Fe-57 atoms or ions produced by beta-decay were not trapped within the SF6 matrix. At 9 K, monomeric FeF2 and FeF3 molecules were produced by reaction of Fe-57 with F atoms released by decomposition of the SF6 molecules. When the temperature of the SF6 solid was increased to 65 K, FeF4 was formed in addition to FeF2 and FeF3. Density functional calculations were performed to confirm the assignments of the candidate species identified in the Mossbauer spectra.

    DOI

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  • Modulating the ground state, stability and charge transport in OFETs of biradicaloid hexahydro-diindenopyrene derivatives and a proposed method to estimate the biradical character

    Tanguy Jousselin-Oba, Masashi Mamada, Atsushi Okazawa, Jérome Marrot, Takayuki Ishida, Chihaya Adachi, Abderrahim Yassar, Michel Frigoli

    Chemical Science   11 ( 44 ) 12194 - 12205  2020年  [査読有り]  [国際誌]

     概要を見る

    <p>Biradicaloid HDIP derivatives show that the Δ<italic>E</italic>S–T gap does not follow the reverse trend of the biradical character but depends more on the delocalization of the radical centres at the outer rings.</p>

    DOI PubMed

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    16
    被引用数
    (Scopus)
  • A useful preparation of ultrasmall iron oxide particles by using arc plasma deposition

    Yumi Ida, Atsushi Okazawa, Kazutaka Sonobe, Hisanori Muramatsu, Tetsuya Kambe, Takane Imaoka, Wang-Jae Chun, Makoto Tanabe, Kimihisa Yamamoto

    RSC Advances   10 ( 68 ) 41523 - 41531  2020年  [査読有り]

     概要を見る

    <p>Finely size-controlled ultrasmall iron oxide particles (IOPs) on graphene nanosheets were usefully prepared by using pulsed arc plasma deposition. The IOPs are composed of a high crystallinity single γ-Fe2O3 component without annealing.</p>

    DOI

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    3
    被引用数
    (Scopus)
  • Chameleonic layered metal–organic frameworks with variable charge-ordered states triggered by temperature and guest molecules

    Jian Chen, Yoshihiro Sekine, Atsushi Okazawa, Hiroyasu Sato, Wataru Kosaka, Hitoshi Miyasaka

    Chemical Science   11 ( 14 ) 3610 - 3618  2020年  [査読有り]

     概要を見る

    <p>A two-dimensional honeycomb layer composed of tetraoxolene-bridged iron subunits whose charge-ordered states are multiply variable <italic>via</italic> thermal treatments and solvation/desolvation is present.</p>

    DOI

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    14
    被引用数
    (Scopus)
  • Navigated Self-Assembly of a Pd2L4 Cage by Modulation of an Energy Landscape under Kinetic Control

    Tomoki Tateishi, Satoshi Takahashi, Atsushi Okazawa, Vicente Martí-Centelles, Jianzhu Wang, Tatsuo Kojima, Paul J. Lusby, Hirofumi Sato, Shuichi Hiraoka

    Journal of the American Chemical Society   141 ( 50 ) 19669 - 19676  2019年12月

    DOI

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    22
    被引用数
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  • Temperature dependence of spherical electron transfer in a nanosized [Fe14] complex.

    Wei Huang, Shuqi Wu, Xiangwei Gu, Yao Li, Atsushi Okazawa, Norimichi Kojima, Shinya Hayami, Michael L Baker, Peter Bencok, Mariko Noguchi, Yuji Miyazaki, Motohiro Nakano, Takumi Nakanishi, Shinji Kanegawa, Yuji Inagaki, Tatsuya Kawae, Gui-Lin Zhuang, Yoshihito Shiota, Kazunari Yoshizawa, Dayu Wu, Osamu Sato

    Nature communications   10 ( 1 ) 5510 - 5510  2019年12月  [査読有り]  [国際誌]

     概要を見る

    The study of transition metal clusters exhibiting fast electron hopping or delocalization remains challenging, because intermetallic communications mediated through bridging ligands are normally weak. Herein, we report the synthesis of a nanosized complex, [Fe(Tp)(CN)3]8[Fe(H2O)(DMSO)]6 (abbreviated as [Fe14], Tp-, hydrotris(pyrazolyl)borate; DMSO, dimethyl sulfoxide), which has a fluctuating valence due to two mobile d-electrons in its atomic layer shell. The rate of electron transfer of [Fe14] complex demonstrates the Arrhenius-type temperature dependence in the nanosized spheric surface, wherein high-spin centers are ferromagnetically coupled, producing an S = 14 ground state. The electron-hopping rate at room temperature is faster than the time scale of Mössbauer measurements (<~10-8 s). Partial reduction of N-terminal high spin FeIII sites and electron mediation ability of CN ligands lead to the observation of both an extensive electron transfer and magnetic coupling properties in a precisely atomic layered shell structure of a nanosized [Fe14] complex.

    DOI PubMed

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    9
    被引用数
    (Scopus)
  • Bifurcation of self-assembly pathways to sheet or cage controlled by kinetic template effect

    Leonardo Hayato Foianesi-Takeshige, Satoshi Takahashi, Tomoki Tateishi, Ryosuke Sekine, Atsushi Okazawa, Wenchao Zhu, Tatsuo Kojima, Koji Harano, Eiichi Nakamura, Hirofumi Sato, Shuichi Hiraoka

    Communications Chemistry   2 ( 1 )  2019年12月

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    12
    被引用数
    (Scopus)
  • Magnetic property and 57Fe Mössbauer analysis of dilute Fe and Nb codoped SrTiO<inf>3-δ</inf>(STO) perovskites

    Kiyoshi Nomura, Shuhei Yamakawa, Miki Kasari, Yuya Koike, Akio Nakanishi, Shiro Kubuki, Atsushi Okazawa

    Hyperfine Interactions   241 ( 1 )  2019年12月  [査読有り]

     概要を見る

    © 2019, Springer Nature Switzerland AG. Dilute Fe and Nb codoped SrTiO3-δ (STO) perovskites were prepared by a complex formation and thermal decomposition method. The structure, magnetization properties and chemical states of Fe and Nb codoped STO perovskites were characterized by XRD, VSM and Mössbauer spectrometry. Mössbauer spectra of 57Fe and Nb codoped STO perovskites consist of paramagnetic doublet and magnetic relaxation components. The 1% Fe + 5% Nb codoped STO sample showed the smallest lattice constant and the largest ferromagnetism among 0.5–4% Fe + 5% Nb codoped STO perovskites. The most distortion of cubic STO lattice and the largest magnetic relaxation in Mössbauer spectrum were observed for the 0.5% Fe and 5% Nb codoped STO perovskite. It is considered that diluted magnetism in this system is related with the deformation of cubic structure due to defects.

    DOI

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    3
    被引用数
    (Scopus)
  • Water-vapor Sensitive Spin-state Switching in an Iron(III) Complex with Nucleobase Pendants Making Flexible Hydrogen-bonded Networks

    Kagesawa Koichi, Ichikawa Yuki, Iguchi Hiroaki, Breedlove Brian K, Li Zhaoyang, Yamashita Masahiro, Okazawa Atsushi, Kosaka Wataru, Miyasaka Hitoshi

    CHEMISTRY LETTERS   48 ( 10 ) 1221 - 1224  2019年10月  [査読有り]

    DOI

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    7
    被引用数
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  • Observation of Proton Transfer Coupled Spin Transition and Trapping of Photoinduced Metastable Proton Transfer State in an Fe(II) Complex.

    Takumi Nakanishi, Yuta Hori, Hiroyasu Sato, Shu-Qi Wu, Atsushi Okazawa, Norimichi Kojima, Takashi Yamamoto, Yasuaki Einaga, Shinya Hayami, Yusuke Horie, Hajime Okajima, Akira Sakamoto, Yoshihito Shiota, Kazunari Yoshizawa, Osamu Sato

    Journal of the American Chemical Society   141 ( 36 ) 14384 - 14393  2019年09月  [査読有り]  [国際誌]

     概要を見る

    An important technique to realize novel electron- and/or proton-based functionalities is to use a proton-electron coupling mechanism. When either a proton or electron is excited, the other one is modulated, producing synergistic functions. However, although compounds with proton-coupled electron transfer have been synthesized, crystalline molecular compounds that exhibit proton-transfer-coupled spin-transition (PCST) behavior have not been reported. Here, we report the first example of a PCST Fe(II) complex, wherein the proton lies on the N of hydrazone and pyridine moieties in the ligand at high-spin and low-spin Fe(II), respectively. When the Fe(II) complex is irradiated with light, intramolecular proton transfer occurs from pyridine to hydrazone in conjunction with the photoinduced spin transition via the PCST mechanism. Because the light-induced excited high-spin state is trapped at low temperatures in the Fe(II) complex-a phenomenon known as the light-induced excited-spin-state trapping effect-the light-induced proton-transfer state, wherein the proton lies on the N of hydrazone, is also trapped as a metastable state. The proton transfer was accomplished within 50 ps at 190 K. The bistable nature of the proton position, where the position can be switched by light irradiation, is useful for modulating proton-based functionalities in molecular devices.

    DOI PubMed

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    17
    被引用数
    (Scopus)
  • Moving Organic Molecules in Crystalline Solids: Gradual Structural Transition and Spin Transition/Crossover

    Kashiro Atsushi, Kyoden Yukiya, Okazawa Atsushi, Ishida Takayuki

    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN   77 ( 7 ) 684 - 695  2019年07月  [査読有り]  [招待有り]

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    1
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  • Determination of iron species, including biomineralized jarosite, in the iron-hyperaccumulator moss Scopelophila ligulata by Mossbauer, X-ray diffraction, and elemental analyses

    H. Nakajima, A. Okazawa, S. Kubuki, Q. Shen, K. Itoh

    BioMetals   32 ( 1 ) 171 - 184  2019年02月  [査読有り]

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  • Preparation of Superparamagnetic Fe3O4 Nanoparticles from Iron Sand Mediated by Soft Template and Their Performance as Antibacterial Agent

    A. Taufiq, A. F. Muyasaroh, Sunaryono, H. Susanto, N. Hidayat, N. Mufti, E. Suarsini, A. Hidayat, A. Okazawa, T. Ishida, Darminto

    Journal of Magnetics   23 ( 3 ) 337 - 344  2018年09月  [査読有り]

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    7
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  • Unique Hydration/Dehydration-Induced Vapochromic Behavior of a Charge-Transfer Salt Comprising Viologen and Hexacyanidoferrate(II)

    Rikako Tanaka, Atsushi Okazawa, Hisashi Konaka, Akito Sasaki, Norimichi Kojima, Nobuyuki Matsushita

    Inorganic Chemistry   57 ( 4 ) 2209 - 2217  2018年02月  [査読有り]

     概要を見る

    We successfully prepared and crystallographically characterized the first intermolecular charge-transfer (CT)-based vapochromic compound, (EV)(H3O)2[Fe(CN)6] (1-Wet, EV2+: 1,1′-diethyl-4,4′-bipyridine-1,1′-diium), an ethyl viologen-containing CT salt. 1-Wet, which is purple in color, is transformed into a brown powder (1-Dry) upon exposure to methanol vapor, drying over silica gel, or heating
    1-Dry returns to 1-Wet upon exposure to water vapor. These color changes are induced by hydration and dehydration, and gravimetric analyses suggest that 1-Dry is the dehydrated form of 1-Wet, namely, (EV)(H)2[Fe(CN)6]. Interestingly, desorption of water molecules from the oxonium ions in 1-Wet produces isolated protons (H+) that remain in 1-Dry as counter cations. Powder X-ray crystal structure analysis of 1-Dry reveals the presence of very short contacts between the nitrogen atoms of adjacent [Fe(CN)6]4- anions in the crystal. The isolated protons are trapped between the nitrogen atoms of cyanido ligands to form very short N···H···N hydrogen bonds. A detailed comparison of the crystal structures of 1-Wet and 1-Dry reveals that hydration and dehydration induce changes in crystal packing and intermolecular CT interactions, resulting in reversible color changes.

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    10
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  • Structural Insight into Order-Disorder Transition and Charge-Transfer Phase Transition in an Iron Mixed-Valence Complex (n-C3H7)4N[FeIIFeIII(dto)3] with a Two-Dimensional Honeycomb Network

    M. Itoi, A. Okazawa, J. Yamaura, S. Maki, T. Komatsu, I. Maurin, E. Codjovi, K. Boukheddaden, N. Kojima

    Inorganic Chemistry   57 ( 21 ) 13728 - 13738  2018年  [査読有り]

    DOI PubMed

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    6
    被引用数
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  • Ionic crystal containing protons (H+) As counter cations: Preparation and crystal structure of a salt of 4,4¤-bipiperidine-1,1¤-diium and hexacyanidoferrate(II)

    Rikako Tanaka, Atsushi Okazawa, Norimichi Kojima, Nobuyuki Matsushita

    Chemistry Letters   47 ( 6 ) 697 - 699  2018年  [査読有り]

     概要を見る

    A molecular salt with a bulky cation and anion, (H2bipip)-(H)2[Fe(CN)6] (1) (H2bipip2+: 4,4¤-bipiperidine-1,1¤-diium), has been prepared. The salt comprises protons (H+) as counter cations. Single-crystal X-ray structure analysis revealed that the proton is trapped between two cyanido ligands of [Fe(CN)6]41 anions, forming a very short N£H+£N hydrogen bond.

    DOI

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    3
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  • A triplet biradical with double bidentate sites based on tert-butyl pyridyl nitroxide as a candidate for strong ferromagnetic couplers

    A. Okazawa, Y. Terakado, T. Ishida, N. Kojima

    New Journal of Chemistry   42   17874 - 17878  2018年  [査読有り]

     概要を見る

    &lt;B&gt;[Back Cover]&lt;/B&gt;

    DOI

  • Magnetic properties of V-substitution effect in an iron mixed valence complex

    Norihiro Shida, Yoshiki Suzawa, Michikazu Inaba, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    POLYHEDRON   136   143 - 148  2017年11月  [査読有り]

     概要を見る

    The iron mixed-valence complex (n-C3H7)(4)N[(FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2) exhibits a novel type of phase transition according electron transfer between FeII and FeIII called charge transfer phase transition (CTPT). The existence of the CTPT highly depends on the 3d metal substitution with Zn, Mn, Cr, or Co for corresponding Fe site in (n-C3H7)(4)N[(FeFeIII)-Fe-II(dto)(3)]. Here, we prepared a series of magnetically diluted complexes (n-C3H7)(4)N[Fe(II)Fe(III)1-xV(III)x(dto)(3)] (x = 01), and carried out investigation of magnetic properties. Judging from the magnetic susceptibility measurement, there is no suppression of the CTPT unlike other 3d metal substituted cases. Moreover, 57Fe Mossbauer spectroscopy revealed that about 60% of FeII sites changed their spin states from high spin to low spin in case of substitution rate for x = 1.00. Since the difference of hardness and softness between metallic ions (Fe-II, Fe-III and V-III) and coordination sites of ligand (O or S in dto), this behavior is explained by the linkage isomerization of bridging ligand in formation process of the complex. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI

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  • Enhanced magnetism of perovskite oxides, Sr(Sn,Fe)O3–δ, by substitution of nonmagnetic Ca and Ti ions

    K. Nomura, S. Suzuki, T. Mizunuma, Y. Koike, A. Okazawa

    Hyperfine Interactions   238   81-1 - 9  2017年10月  [査読有り]

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    1
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  • 57Fe and 119Sn Mössbauer study of SrSnO3-δ doped with Fe and Sb under external magnetic fields

    K. Nomura, S. Suzuki, Y. Koike, A. Okazawa, Y. Kobayashi, M. Kaneko

    Hyperfine Interactions   238   70-1 - 8  2017年10月  [査読有り]

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  • Studies on Nanostructure and Magnetic Behaviors of Mn-Doped Black Iron Oxide Magnetic Fluids Synthesized from Iron Sand

    Ahmad Taufiq, Sunaryono, Nurul Hidayat, Arif Hidayat, Edy Giri Rachman Putra, Atsushi Okazawa, Isao Watanabe, Norimichi Kojima, Suminar Pratapa, Darminto

    NANO   12 ( 9 ) 1750110-1 - 11  2017年09月  [査読有り]

     概要を見る

    Manganese (Mn)-doped black iron oxide (Fe3O4) magneticuids in the system of MnxFe(3-x)O(4) were successfully synthesized from natural magnetite (iron sand) by using co-precipitation method at room temperature. The analyses of the small angle neutron scattering (SANS) data by applying a log-normal sphere with a mass fractal models for x = 0 and x = 0: 25 and two lognormal spheres with a single mass fractal models for x 0: 5, 0.75 and 1 revealed that the primary particles of the MnxFe(3-x)O(4) fluids tended to decrease from 3.8 nm to 1.5nm along with the increasing fraction of Mn contents. The fractal dimension (D) increased from about 1.2 to 2.7 as the Mn contents were increasing; which physically represents an aggregation of the MnxFe(3-x)O(4) particles in the uids growing up from 1 to 3 dimensions to consolidate a more compact structure. The magnetization curves of the fluids exhibited an increasing saturation magnetization from x = 0 to x = 0: 25, and a decreasing on x = 0.5 and 0.75, with the maximum achievement of x = 1. These phenomena may probably be due to the combined e r ects, arising from cationic and dopant distributions, aggregation and its size, and also fractal dimension. Furthermore, the decrease of blocking temperature of the MnxFe(3-x)O(4) magneticuids could be associated with the reduced particle sizes, while the freezing temperature had its highest peak intensity when it collectively occurred with the blocking temperature at a similar point of about 270 K.

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  • Halogen substituent effect on the spin-transition temperature in spin-crossover Fe(III) compounds bearing salicylaldehyde 2-pyridyl hydrazone-type ligands and dicarboxylic acids

    Takumi Nakanishi, Atsushi Okazawa, Osamu Sato

    Inorganics   5 ( 3 ) 53-1 - 9  2017年09月  [査読有り]

     概要を見る

    Four Fe(III) spin-crossover (SCO) compounds, [Fe(HL1)2](HCl4TPA) (1-Cl), [Fe(HL1)2](HBr4TPA) (1-Br), [Fe(HL2)2](HCl4TPA) (2-Cl), and [Fe(HL2)2](HBr4TPA) (2-Br) (HL1 = 4-chloro-2-nitro-6-(1-(2-(pyridine-2-yl)hydrazono)ethyl)phenolate
    HL2 = 4-bromo-2-nitro-6-(1-(2- (pyridine-2-yl)hydrazono)ethyl)phenolate
    HCl4TPA = 2,3,5,6-tetrachloro-4-carboxybenzoate
    and HBr4TPA = 2,3,5,6-tetrabromo-4-carboxybenzoate), were synthesized to investigate the halogen substituent change effect in salicylaldehyde 2-pyridyl hydrazone-type ligands and dicarboxylic acids in SCO complexes to the spin-transition temperature. Crystal structure analyses showed that these compounds were isostructural. In addition, a one-dimensional hydrogen-bonded column was formed by the dicarboxylic acid anion and weak hydrogen bonds between the Fe(III) complexes. From Mössbauer spectroscopy and magnetic property measurements, these compounds were confirmed to exhibit gradual SCO. The spin-transition temperature can be shifted by changing the halogen substituent in the salicylaldehyde 2-pyridyl hydrazone-type ligands and dicarboxylic acids without changing the molecular arrangement in the crystal packing.

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    8
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  • Control of spin-crossover phenomena in one-dimensional triazole-coordinated iron(II) complexes by means of functional counter ions

    Akira Sugahara, Hajime Kamebuchi, Atsushi Okazawa, Masaya Enomoto, Norimichi Kojima

    Inorganics   5 ( 3 ) 50-1 - 23  2017年09月  [査読有り]

     概要を見る

    The spin-crossover (SCO) phenomenon between a high-spin and a low-spin state has attracted much attention in the field of materials science. Among the various kinds of SCO complexes, the triazole-bridged iron(II) polymeric chain system, [Fe(II)(R-trz)3]X2.xH2O (where trz is triazole and X is the anion), exhibiting the SCO phenomenon with thermal hysteresis around room temperature, has been extensively studied from the viewpoint of molecular memory and molecular devices. In connection with this system, we have controlled the SCO phenomenon according to the characteristic properties of counter ions. In the case of X being CnH2n+1SO3 -, the spin transition temperature (T1/2) increases with increasing the length (n) of the alkyl chain of the counter ion and saturates above n = 5, which is attributed to the increase in the intermolecular interaction of the alkyl chains of CnH2n+1SO3 -, called the fastener effect. The hysteresis width of T1/2 decreases with increasing n, showing the even-odd, also known as parity, effect. In the cases where X is toluenesulfonate (tos: CH3C6H4SO3 -) and aminobenzenesulfonate (abs: NH2C6H4SO3 -), T1/2 and its hysteresis width vary drastically with the structural isomerism (ortho-, metha-, and para-substitution) of counter ions, which implies the possibility of photoinduced spin transition by means of the photoisomerization of counter ions. From this strategy, we have synthesized [Fe(II)(NH2-trz)3](SP150)2·2H2O (SP150 = N-alkylsulfonated spiropyran) and investigated the SCO phenomenon. Moreover, we have developed [Fe(II)(R-trz)3]@Nafion films exhibiting spin transition around room temperature, where the Nafion membrane behaves as a counter anion as well as a transparent substrate, and investigated the photogenerated high-spin state below 35 K. The lifetime of the photogenerated high-spin state strongly depends on the intensity of irradiated light.

    DOI

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    15
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  • Magneto-Structural Relationship on Strong Exchange Interactions between Chelating Nitroxide Radical and Transition-Metal Spins

    A. Okazawa

    IOP Conference Series: Materials Science and Engineering   202 ( 1 ) 012002-1 - 9  2017年05月  [査読有り]

     概要を見る

    To develop room-temperature molecule-based magnets, metal-radical approach is one of the most promising strategies. Strong magnetic interactions beyond a thermal energy of room temperature are essential for achieving such coveted materials. We have developed 2-pyridyl tert-butyl nitroxide (2pyNO) derivatives as a chelating radical ligand with a copper(II) or nickel(II) ion. The torsion angle (φ) around M-O-N-C2py is a useful metric in describing correlation between the structure and metal-radical exchange coupling 2J (defined as H = -2JΣSi •Si +1). Although we previously reported such a magneto-structural correlation, in this paper we updated the plot of 2J versus φ by dividing into two categories: the hexacoordinatenickel(II) and copper(II) complexes. An empirical linear correlation was formulated for both Cu and Ni categories, as 2J/k B = a + b|φ| with a = 503(112) K and b = -36(3) K deg-1 and with a = 449(46) K and b = -21.0(17) K deg-1, respectively. In the latter plot we confirm that the relationship can be generalized for the oxoverdazyl and dithiadiazolyl systems as well as the 2pyNO systems. The results are supported by the calculations based on the density functional theory.

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    11
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  • Synthesis and Magnetic Properties of Linear Two-Coordinate Monomeric Diaryliron(II) Complexes Bearing Fused-Ring Bulky “Rind” Groups

    S. Goda, M. Nikai, M. Ito, D. Hashizume, K. Tamao, A. Okazawa, N. Kojima, H. Fueno, K. Tanaka, Y. Kobayashi, T. Matsuo

    Chemistry Letters   45 ( 6 ) 634 - 636  2016年06月  [査読有り]

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  • Small-Angle X-Ray Scattering Study on PVA/Fe3O4 Magnetic Hydrogels

    Sunaryono, Ahmad Taufiq, Edy Giri Rahman Putra, Atsushi Okazawa, Isao Watanabe, Norimichi Kojima, Supagorn Rugmai, Siriwat Soontaranon, Mohammad Zainuri, Triwikantoro, Suminar Pratapa, Darminto

    NANO   11 ( 3 ) 1650027-1 - 12  2016年03月  [査読有り]

     概要を見る

    A synchrotron small-angle X-ray scattering (SAXS) study on PVA/Fe3O4 magnetic hydrogels has been performed to investigate the effect of clustering on their magnetic properties. The hydrogels were prepared through freezing-thawing (F-T) processes. The structure, morphology and magnetic properties of magnetite (Fe3O4) nanoparticles (NPs) were investigated using X-ray diffractometry (XRD), transmission electron microscopy (TEM) and a superconducting quantum interference device (SQUID) magnetometer, respectively. In this study, SAXS data were used to reveal the structural dimensions of the magnetite and its distribution in the polymer-rich PVA and magnetic hydrogels. As calculated using the Beaucage and Teubner-Strey models, the average of the structural dimensions of the PVA hydrogels was 3.9 nm (crystallites), while the average distance between crystallites was approximately 18 nm. Further analysis by applying a two-lognormal distribution showed that the magnetite NPs comprised secondary particles with a diameter of 9.6 nm that were structured by primary particles (similar to 3.2 nm). A two-lognormal distribution function has also been used in describing the size distributions of magnetite NPs in magnetic hydrogels. The clusters of magnetite NPs in the magnetic hydrogels are significantly reduced from 30.4 nm to 12.8 nm with decreasing concentration of the NPs magnetite from 15 wt.% to 1 wt.%. The saturation magnetization values of the magnetite NPs, the 15% and 1% magnetic hydrogels were 34.67 emu/g, 6.52 emu/g and 0.37 emu/g, respectively.

    DOI

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    24
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  • Magnetic property and Mössbauer analysis of SrSn1−xFexO3 prepared by a sol-gel method

    K. Nomura, S. Suzuki, Y. Koike, H. Li, A. Okazawa, N. Kojima

    Hyperfine Interactions   237 ( 1 ) 26-1 - 10  2016年02月  [査読有り]

    DOI

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    5
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  • Mössbauer and XRD analysis of corrosion products on weathering steel treated by wet-dry cycles using various solutions

    M. Oyabu, K. Nomura, Y. Koike, A. Okazawa

    Hyperfine Interactions   237 ( 1 ) 68-1 - 7  2016年02月  [査読有り]

    DOI

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    2
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  • 1706 - Proton-responsive emission properties in cyclometalated iridium(III) complex film, [IrIII(bdp)3]@Nafion (bdp = 2,4’-(benzene-1,3-diyl)dipyridine)

    Hajime Kamebuchi, Yu Fujimura, Atsushi Okazawa, Makoto Tadokoro, Norimichi Kojima

    The 2015 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2015)    2015年12月  [査読有り]

  • Nanoscale Clustering and Magnetic Properties of Mn (x) Fe3-x O-4 Particles Prepared from Natural Magnetite

    Ahmad Taufiq, Sunaryono, Edy Giri Rachman Putra, Atsushi Okazawa, Isao Watanabe, Norimichi Kojima, Suminar Pratapa, Darminto

    JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM   28 ( 9 ) 2855 - 2863  2015年09月  [査読有り]

     概要を見る

    A series of Mn (x) Fe3-x O-4 (0 a parts per thousand currency sign x a parts per thousand currency sign 1) nanoparticles was successfully synthesized via a simple coprecipitation method. The starting material was a natural magnetite purified from local iron sand. Crystallite nanoparticles were produced by drying without using a high calcination temperature. Rietveld analysis of the X-ray diffractometry (XRD) data for all samples demonstrated that the Mn ions partially substituted the Fe ions in the spinel cubic structure of the Fe3O4 to form Mn (x) Fe3-x O-4 phases. We applied two lognormal spherical and single mass fractal models to the analysis of the small-angle neutron scattering (SANS) data and revealed that the primary Mn (x) Fe3-x O-4 particles ranged in size from 1.5 to 3.8 nm and formed three-dimensional clusters as secondary structures. The samples displayed superparamagnetic behavior, having the saturation magnetization which was most likely influenced by the competing contribution from Mn, the sizes of the primary particles, and their clusters. Further analysis revealed that the zero-field-cooled and field-cooled curves of the Mn (x) Fe3-x O-4 nanoclusters exhibited a superparamagnetic phenomenon with the lowest magnetic blocking temperature approximately 145 K.

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  • Development of a Photoresponsive Organic-Inorganic Hybrid Magnet: Layered Cobalt Hydroxides Intercalated with Spiropyran Anions

    Naru Tanaka, Atsushi Okazawa, Akira Sugahara, Norimichi Kojima

    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   88 ( 8 ) 1150 - 1155  2015年08月  [査読有り]

     概要を見る

    To develop an organic inorganic hybrid photomagnet, we performed the intercalation of sulfonate-substituted spiropyran anions into layered cobalt hydroxides, obtaining the photoresponsive compound, Co(OH)(1.84)(nSPSO(3))(0.16)center dot 0.8H(2)O (CoLHSP; nSPSO(3): 1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-indoline]-5'-sulfonate). After UV irradiation (313 nm), the optical and magnetic properties of CoLHSP clearly changed. A new band emerged in the absorption spectrum at 564 nm, corresponding to the pi-pi* transition in the open form of nSPSO(3). Moreover, the photoisomerization of nSPSO(3) induced a new ferrimagnetic phase transition at 10K in the temperature dependence of DC and AC magnetic susceptibilities in addition to the ferrimagnetic phase transition at 15K for the unirradiated sample. Analyzing the magnetic measurements before and after UV irradiation, we estimated the phototransformation ratio of the magnetic phase in CoLHSP at approximately 40%.

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    5
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  • Study on spin configuration in photoresponsive iron mixed-valence complexes by Mössbauer spectroscopy

    A. Okazawa, J. Yoshida, N. Kida, I. Kashima, W. Murata, M. Enomoto, N. Kojima

    Hyperfine Interactions   226 ( 1-3 ) 351 - 357  2014年04月  [査読有り]

    DOI

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    1
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  • Sol-gel synthesis and dilute magnetism of nano MgO powder doped with Fe

    Kiyoshi Nomura, Souichirou Taya, Atsushi Okazawa, Norimichi Kojima

    HYPERFINE INTERACTIONS   226 ( 1-3 ) 161 - 169  2014年04月  [査読有り]

     概要を見る

    Mg oxides doped with 1 % Fe-57 were prepared by a sol-gel method, and annealed at various temperatures. Nano-size Mg oxides were characterized by Mossbauer spectrometry, magnetization and XRD measurements. The crystalline size of MgO increases with increase of annealing temperature. Samples annealed at 600 A degrees C and 800 A degrees C gave only doublet peaks of paramagnetic Fe3+ in Mossbauer spectra although Fe3+ doping into MgO induced a distorted structure and showed weak ferromagnetism. It is considered that the magnetic property is due to defect induced magnetism by doping Fe3+ into MgO. For a sample heated at 1000 A degrees C, it is found from low temperature Mossbauer spectra that Fe3+ species are located at the core and shell of fine MgFe2O4 grains and diluted in MgO matrix.

    DOI

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    3
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  • Photochromic Property of Anionic Spiropyran with Sulfonate-substituted Indoline Moiety

    Akira Sugahara, Nara Tanaka, Atsushi Okazawa, Nobuyuld Matsushita, Norimichi Kojima

    CHEMISTRY LETTERS   43 ( 3 ) 281 - 283  2014年03月  [査読有り]

     概要を見る

    For fabricating photoresponsive multifunctional materials, we have developed the potassium salt of a new anionic spiropyran, 1',3',3'-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2'-indoline]-5'-sulfonate (1(-)), with the sulfonate group present on the indoline moiety and whose crystal structure was revealed by single-crystal X-ray diffraction analysis. The photochromism of 1.K was demonstrated at room temperature in the KBr-diluted state, as well as in solution. The protonated spiropyran 1H shows negative photochromism.

    DOI J-GLOBAL

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    12
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  • Abrupt Spin Transition with Thermal Hysteresis of Iron(III) Complex [Fe-III(Him)(2)(hapen)]AsF6 (Him = Imidazole, H(2)hapen = N,N '-Bis(2-hydroxyacetophenylidene)ethylenediamine)

    Takeshi Fujinami, Masataka Koike, Naohide Matsumoto, Yukinari Sunatsuki, Atsushi Okazawa, Norimichi Kojima

    INORGANIC CHEMISTRY   53 ( 4 ) 2254 - 2259  2014年02月  [査読有り]

     概要を見る

    The solvent-free spin crossover iron(III) complex [Fe-III(Him)(2)(hapen)]AsF6 (Him = imidazole, H(2)hapen = bis(2-hydroxyacetophenylidene)ethylenediamine), exhibiting thermal hysteresis, was synthesized and characterized. The Fern ion has an octahedral coordination geometry, with N2O2 donor atoms of the planar tetradentate ligand (hapen) and two nitrogen atoms of two imidazoles at the axial positions. One of two imidazoles is hydrogen-bonded to the phenoxo oxygen atom of hapen of the adjacent unit to give a hydrogen-bonded one-dimensional chain, while the other imidazole group is free from hydrogen bonding. The temperature dependencies of the magnetic susceptibilities and Mossbauer spectra revealed an abrupt spin transition between the high-spin (S = 5/2) and low-spin (S = 1/2) states, with thermal hysteresis.

    DOI J-GLOBAL

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    21
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  • Study on static and dynamic spin-crossover tripyrazolylmethane iron(II) complexes by using μSR spectroscopy

    N. Kojima, H. Kobayashi, A. Okazawa, I. Kawasaki, I. Watanabe

    RIKEN Accelerator Progress Report   47   258  2014年  [査読有り]

  • A tricky water molecule coordinated to a verdazyl radical-iron(II) complex: a multitechnique approach

    Hajime Kamebuchi, Masashi Okubo, Atsushi Okazawa, Masaya Enomoto, Jun Harada, Keiichiro Ogawa, Goro Maruta, Sadamu Takeda, Norimichi Kojima, Cyrille Train, Michel Verdaguer

    PHYSICAL CHEMISTRY CHEMICAL PHYSICS   16 ( 19 ) 9086 - 9095  2014年  [査読有り]

     概要を見る

    The first iron complexes of high-spin iron(II) species directly coordinated to verdazyl radicals, [Fe-11(vdCOO)(2)(H2O)(2)].2H(2)O (1; vdCOO(-) = 1,5-dimethyl-6-oxo-verdazyl-3-carboxylate) and [Fe-11(vdCOO)(2)(D2O)(2)].2D(2)O (2), were synthesized. The crystal structure of 1 was investigated by single-crystal X-ray diffraction at room temperature and at 90 K. The compound crystallizes in the P1 space group with no phase transition between 300 and 90 K. The crystals are composed of discrete [Fe-11(vdCOO)(2)(H2O)(2)] complexes and crystallization water molecules. In the complex, two vdCOO(-) ligands coordinate to the iron(II) ion in a head-to-tail arrangement and two water molecules complete the coordination sphere. The Fe-X (X = O, N) distances vary in the 2.069-2.213 A range at 300 K and in the 2.0679-2.2111 A range at 90 K, indicating that the iron(II) ion is in its high-spin (HS) state at both temperatures. At 300 K, one of the coordinated water molecules is H-bonded to two crystallization water molecules whereas the second one appears as loosely H-bonded to the two oxygen atoms of the carboxylate group of two neighboring complexes. At 90 K, the former H-bonds remain essentially the same whereas the second coordinated water molecule reveals a complicated behavior appearing simultaneously as tightly H- bonded to two oxygen atoms and non-H-bonded. The Fe-57 Mossbauer spectra, recorded between 300 K and 10 K, give a clue to this situation. They show two sets of doublets typical of HS iron(II) species whose intensity ratio varies smoothly with temperature. It demonstrates the existence of an equilibrium between the high temperature and low temperature forms of the compounds. The solid-state magic angle spinning H-2 NMR spectra of 2 were recorded between 310 K and 193 K. The spectra suggest the existence of a strongly temperature- dependent motion of one of the coordinated water molecules in the whole temperature range. Variable- temperature magnetic susceptibility measurements indicate an antiferromagnetic interaction (J(Fe-vd) = -27.1 cm(-1); H = -J(ij)S(i)S(j)) of the HS iron(II) ion and the radical spins with high g(Fe) and D-Fe values (g(Fe) = 2.25, D-Fe = +3.37 cm(-1)) for the HS iron(II) ion. Moreover, the radicals are strongly antiferromagnetically coupled through the iron(II) center (J(vd-vd) = -42.8 cm(-1)). These last results are analysed based on the framework of the magnetic orbitals formalism.

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    6
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  • Cation size effect on photomagnetism and charge transfer phase transition of iron mixed-valence complexes with spiropyrans

    Junya Yoshida, Noriyuki Kida, Atsushi Okazawa, Norimichi Kojima

    POLYHEDRON   66   102 - 107  2013年12月  [査読有り]

     概要を見る

    We have investigated the magnetic properties of a photoresponsive organic inorganic hybrid system, (SP-R)[(FeFeIII)-Fe-II(dto)(3)](SP = spiropyran; R = Me, Et, Pr; dto = C2O2S2), under hydrostatic pressures. At ambient pressure, (SP-Et)[(FeFeIII)-Fe-II(dto)(3)] and (SP-Pr)[(FeFeIII)-Fe-II(dto)(3)] undergo one and two ferromagnetic phase transitions corresponding to the high-temperature phase with the spin configuration of Fe-II(S = 2)-Fe-III(S = 1/2), while (SP-Me)[(FeFeIII)-Fe-II(dto)(3)] undergoes two ferromagnetic phase transitions corresponding to the coexistence of the high-temperature phase and the low-temperature phase with the spin configuration of Fe-II(S = 0)-Fe-III(S = 5/2). Under hydrostatic pressures, (SP-R)[(FeFeIII)-Fe-II(dto)(3)] (R = Et, Pr) undergo a new ferromagnetic phase transition corresponding to the low-temperature phase caused by the pressure-induced charge transfer phase transition. (C) 2013 Elsevier Ltd. All rights reserved.

    DOI J-GLOBAL

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    5
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  • Exchange Coupling and Its Chemical Trend Studied by High-Frequency EPR on Heterometallic [Ln(2)Ni] Complexes

    Atsushi Okazawa, Takashi Shimada, Norimichi Kojima, Shunsuke Yoshi, Hiroyuki Nojiri, Takayuki Ishida

    INORGANIC CHEMISTRY   52 ( 23 ) 13351 - 13355  2013年12月  [査読有り]

     概要を見る

    We applied high-frequency electron paramagnetic resonance to trinuclear 4f-3d heterometallic complexes, [{Ln(hfac)(3)}(2){Ni(dpk)(2)(py)(2)}] (Ln = Y, Gd, Tb, and Ho; hfac = hexafluoroacetylacetonate, dpk = di-2-pyridyl ketoximate, and py = pyridine), and determined the exchange parameter J(Ln-Ni) as well as nickel(II) zero-field splitting parameters. In contrast to the antiferromagnetic Dy analogue, ferromagnetic couplings were precisely characterized as J(Gd-Ni)/k(B) = +0.301(4) K, J(Tb-Ni)/k(B) = +0.216(12) K, and J(Ho-Ni)/k(B) = +0.110(3) K (defined as -J(Ln-Ni)Sigma J(Ln)(z)S(Ni)).

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    13
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  • Alternating Ferro-and Antiferromagnetic Couplings in One-Dimensional Chain Hexachlorodicuprate(II), (MV)[CuCl3]2 (MV= Methyl Viologen)

    Y. Seki, A. Okazawa, M. Enomoto, J. Harada, K. Ogawa, N. Kojima

    Current Inorganic Chemistry   3 ( 2 ) 94 - 100  2013年06月  [査読有り]

    DOI

  • Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks

    Yuta Homma, Atsushi Okazawa, Takayuki Ishida

    TETRAHEDRON LETTERS   54 ( 24 ) 3120 - 3123  2013年06月  [査読有り]

     概要を見る

    We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were vertical bar D vertical bar/hc = 2.52 x 10(-2) cm(-1) and vertical bar E vertical bar/hc = 2.34 x 10(-3) cm(-1) in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/k(B) = +18.5(5) K in frozen toluene-ethanol. DFT calculation supports the ground triplet state of pmbNO. The reaction of pmbNO with Cu(hfac)(2) gave [Cu-3(pmbNO)(2)(hfac)(4)], and the structure was determined by X-ray crystallographic analysis. Though the ligand was reduced to be an anion radical, pmbNO is confirmed to work as a rigid bridge, and the nitroxide oxygen atoms can ligate the metal ions. (C) 2013 Elsevier Ltd. All rights reserved.

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    10
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  • Reversible Solid State Redox of an Octacyanometallate-Bridged Coordination Polymer by Electrochemical Ion Insertion/Extraction

    Masashi Okubo, Koichi Kagesawa, Yoshifumi Mizuno, Daisuke Asakura, Eiji Hosono, Tetsuichi Kudo, Haoshen Zhou, Kotaro Fujii, Hidehiro Uekusa, Shin-ichi Nishimura, Atsuo Yamada, Atsushi Okazawa, Norimichi Kojima

    INORGANIC CHEMISTRY   52 ( 7 ) 3772 - 3779  2013年04月  [査読有り]

     概要を見る

    Coordination polymers have significant potential for new functionality paradigms due to the intrinsic tunability of both their electronic and structural properties. In particular, octacyanometallate-bridged coordination polymers have the extended structural and magnetic diversity to achieve novel functionalities. We demonstrate that [Mn(H2O)][Mn(HCOO)(2/3)(H2O)(2/3)](3/4)[Mo(CN)(8)]center dot H2O can exhibit electrochemical alkali-ion insertion/extraction with high durability. The high durability is explained by the small lattice change of less than 1% during the reaction, as evidenced by ex situ X-ray diffraction analysis. The ex situ X-ray absorption spectroscopy revealed reversible redox of the octacyanometallate. Furthermore, the solid state redox of the paramagnetic [Mo-V(CN)(8)](3-)/diamagnetic[Mo-IV(CN)(8)](4-) couple realizes magnetic switching.

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    25
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  • Long-range and short-range orderings in K4Fe4P5O20 with a natrolite-like framework

    Zhangzhen He, Weilong Zhang, Wendan Cheng, Atsushi Okazawa, Norimichi Kojima

    DALTON TRANSACTIONS   42 ( 16 ) 5860 - 5865  2013年  [査読有り]

     概要を見る

    K4Fe4P5O20 shows an interesting natrolite-like structure with a spin-tetrahedron lattice built by mixed valence Fe ions. Single crystals of the title compound are successfully grown by the flux method using KF as flux. Magnetic results combined from magnetic, heat capacity, and Fe-57 Mossbauer spectra measurements show that K4Fe4P5O20 possesses a short-range magnetic ordering at similar to 13 K and a long-range ordering at similar to 7 K. Magnetic anisotropy of K4Fe4P5O20 is observed between H parallel to c and H perpendicular to c, suggesting that the c-axis is the magnetic easy-axis. The spin arrangements in the system are suggested to be ferrimagnetic along the natrolite chains.

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    10
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  • Electrochemical Mg2+ intercalation into a bimetallic CuFe Prussian blue analog in aqueous electrolytes

    Yoshifumi Mizuno, Masashi Okubo, Eiji Hosono, Tetsuichi Kudo, Katsuyoshi Oh-ishi, Atsushi Okazawa, Norimichi Kojima, Ryosuke Kurono, Shin-ichi Nishimura, Atsuo Yamada

    JOURNAL OF MATERIALS CHEMISTRY A   1 ( 42 ) 13055 - 13059  2013年  [査読有り]

     概要を見る

    Mg2+ intercalation/deintercalation is achieved by using aqueous electrolytes and Prussian blue analog electrodes. Ex situ X-ray diffraction evidenced the solid solution process of Mg2+ intercalation/deintercalation, while the Fe-57 Mossbauer spectroscopy and X-ray absorption near edge structure revealed redox of both Cu and Fe.

    DOI J-GLOBAL

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    134
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  • Anionic Iron Complexes with a Bond between an Ate-Type Pentacoordinated Germanium and an Iron Atom

    Naokazu Kano, Naohito Yoshinari, Yusuke Shibata, Mariko Miyachi, Takayuki Kawashima, Masaya Enomoto, Atsushi Okazawa, Norimichi Kojima, Jing-Dong Guo, Shigeru Nagase

    ORGANOMETALLICS   31 ( 23 ) 8059 - 8062  2012年12月  [査読有り]

     概要を見る

    The first stable anionic iron(0) complexes bearing an ate-type pentacoordinated germanium(IV) ligand were synthesized. The X-ray crystallographic analysis shows trigonal-bipyramidal and piano-stool geometries of germanium and iron, respectively. The complexes have moderately electron-rich iron centers and polar Ge-Fe bonds which can be cleaved by oxidation.

    DOI J-GLOBAL

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    15
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  • Precise Electrochemical Control of Ferromagnetism in a Cyanide-Bridged Bimetallic Coordination Polymer

    Yoshifumi Mizuno, Masashi Okubo, Koichi Kagesawa, Daisuke Asakura, Tetsuichi Kudo, Haoshen Zhou, Katsuyoshi Oh-ishi, Atsushi Okazawa, Norimichi Kojima

    INORGANIC CHEMISTRY   51 ( 19 ) 10311 - 10316  2012年10月  [査読有り]

     概要を見る

    Magnetic coordination polymers can exhibit controllable magnetism by introducing responsiveness to external stimuli. This report describes the precise control of magnetism of a cyanide-bridged bimetallic coordination polymer (Prussian blue analogue: PBA) through use of an electrochemical quantitative Li ion titration technique, i.e., the galvanostatic intermittent titration technique (GITT). K0.2Ni[Fe(CN)(6)](0.7)center dot 4.7H(2)O (NiFe-PBA) shows Li ion insertion/extraction reversibly accompanied with reversible Fe3+/Fe2+ reduction/oxidation. When Li ion is inserted quantitatively into NiFe-PBA, the ferromagnetic transition temperature T-C gradually decreases due to reduction of paramagnetic Fe3+ to diamagnetic Fe2+, and the ferromagnetic transition is completely suppressed for Li-0.6(NiFe-PBA). On the other hand, T-C increases continuously as Li ion is extracted due to oxidation of diamagnetic Fe2+ to paramagnetic Fe3+, and the ferromagnetic transition is nearly recovered for Li-0(NiFe-PBA). Furthermore, the plots of T-C as a function of the amount of inserted/extracted Li ion x are well consistent with the theoretical values calculated by the molecular-field approximation.

    DOI J-GLOBAL

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    47
    被引用数
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  • Effect of Nonmagnetic Substitution on the Magnetic Properties and Charge-Transfer Phase Transition of an Iron Mixed-Valence Complex, (n-C3H7)(4)N[(FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2)

    Hiromichi Ida, Atsushi Okazawa, Norimichi Kojima, Ryo Shimizu, Yasuhiro Yamada, Masaya Enomoto

    INORGANIC CHEMISTRY   51 ( 16 ) 8989 - 8996  2012年08月  [査読有り]

     概要を見る

    The iron mixed-valence complex (n-C3H7)(4)N[(FeFeIII)-Fe-II(dto)(3)] exhibits a novel type of phase transition called charge-transfer phase transition (CTPT), where the thermally induced electron transfer between Fe-II and Fe-III occurs reversibly at similar to 120 K, in addition to the ferromagnetic phase transition at T-C = 7 K. To investigate the mechanism of the CTPT, we have synthesized a series of magnetically diluted complexes (n-C3H7)(4)N[(Fe1-xZnxFeIII)-Zn-II-Fe-II(dto)(3)] (dto = C2O2S2; x = 0-1), and carried out magnetic susceptibility and dielectric constant measurements and Fe-57 Mossbauer spectroscopy. With increasing Zn-II concentration (x), the CTPT is gradually suppressed and disappears at x approximate to 0.13. On the other hand, the ferromagnetic transition temperature (T-C) is initially enhanced from 7 K to 12 K between x = 0.00 and 0.05, despite the nonmagnetic nature of Zn-II ions, and then it decreases monotonically from 12 K to 3 K with increasing Zn-II concentration. This anomalous dependence of T-C on Zn-II concentration is related to a change in the spin configuration of the ferromagnetic state caused by the partial suppression of the CTPT.

    DOI J-GLOBAL

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    7
    被引用数
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  • K4Fe4P5O20: A New Mixed Valence Microporous Compound with Elliptical Eight-Ring Channels

    Zhangzhen He, Weilong Zhang, Wendan Cheng, Atsushi Okazawa, Norimichi Kojima

    INORGANIC CHEMISTRY   51 ( 14 ) 7469 - 7471  2012年07月  [査読有り]

     概要を見る

    A new small-pore compound K4Fe4P5O20 was obtained by conventional solid-state reaction in a closed crucible. The crystal structure is constructed by Fe4P5O20 units forming chains along the c axis and elliptical eight-ring channels on the a-b plane in which K cations locate inside. Such structural characteristics seem to be quite similar to those seen in the natrolite family. However, Fe ions in K4Fe4P5O20 have trigonal-bipyramidal instead of common tetrahedral coordination. Furthermore, our experimental results combined from magnetic susceptibility and Fe-57 Mossbauer spectrum measurements show mixed valence Fe3+/Fe2+ in the titled material. To the best of our knowledge, this is the first example that contains mixed valence iron ions in a so-called natrolite framework.

    DOI J-GLOBAL

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    2
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  • Fabrication of a Cyanide-Bridged Coordination Polymer Electrode for Enhanced Electrochemical Ion Storage Ability

    Daisuke Asakura, Masashi Okubo, Yoshifumi Mizuno, Tetsuichi Kudo, Haoshen Zhou, Kazumichi Ikedo, Takashi Mizokawa, Atsushi Okazawa, Norimichi Kojima

    JOURNAL OF PHYSICAL CHEMISTRY C   116 ( 15 ) 8364 - 8369  2012年04月  [査読有り]

     概要を見る

    Host frameworks with the ability to store guest ions are very important in a wide range of applications including electrode materials for Li-ion batteries. In this report, we demonstrate that the ion storage ability of the cyanide-bridged coordination polymer (Prussian blue analogue, PBA) can be enhanced by suppressing vacancy formation. K-ions in the vacancy-suppressed PBA framework K1.72Mn[Mn(CN)(6)](0.93)center dot square(0.07).0.65H(2)O (square: a [Mn(CN)(6)](4-) defect) were electrochemically extracted. The open circuit voltages (OCVs) during K-ion extraction exhibited two specific plateaus at 3.0 and 3.7 V vs Li/Li+. Ex situ X-ray diffraction and IR spectroscopy revealed drastic structural and electronic changes during K-ion extraction. Furthermore, after K-ion extraction, the vacancy-suppressed PBA framework was applied to the cathode material for a Li-ion battery. The charge/discharge experiments revealed that the framework can accommodate a large amount of Li-ions.

    DOI J-GLOBAL

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    93
    被引用数
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  • Study on the ferromagnetic state in iron mixed-valence complexes, A[FeIIFeIII(dto)3] (A = (n-CnH2n + 1)4N; dto = C2S2O2) by means of Mössbauer spectroscopy

    Y. Ono, A. Okazawa, M. Enomoto, N. Kojima

    Hyperfine Interactions   207 ( 1-3 ) 139 - 143  2012年03月  [査読有り]

    DOI J-GLOBAL

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    1
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  • Oximato-bridged light-lanthanide Ln(4)Cu complexes showing ferromagnetic Ln-Cu exchange coupling

    Kei Fujiwara, Atsushi Okazawa, Norimichi Kojima, Go Tanaka, Shunsuke Yoshii, Hiroyuki Nojiri, Takayuki Ishida

    CHEMICAL PHYSICS LETTERS   530   49 - 54  2012年03月  [査読有り]

     概要を見る

    Heterometallic pentanuclear coordination compounds [Ln(4)(3+)Cu(2+)] involving light lanthanide ions, Ce, Pr, Nd, Sm, and Eu, were synthesized and structurally characterized. The exchange interactions between the Ln and Cu ions were evaluated by high-frequency electron paramagnetic resonance and magnetization studies, clarifying the presence of ferromagnetic exchange couplings in Nd-Cu (J(Nd-Cu)/k(B) = +0.30(6) K) and Sm-Cu (J(Sm-Cu)/k(B) = +2.08(3) K), very small couplings in Ce-Cu and Pr-Cu, and the absence in Eu-Cu. A significant chemical trend is found in the order of the atomic number. (C) 2012 Elsevier B. V. All rights reserved.

    DOI J-GLOBAL

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    15
    被引用数
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  • Study on the spin-equilibrium and the succeeding magnetic phase transitions in the iron(III) μSR spectroscopy

    N. Kojima, K. Kagesawa, A. Okazawa, I. Watanabe

    RIKEN Accelerator Progress Report,   45   194  2012年  [査読有り]

  • Size effect of intercalated cation on the charge transfer phase transition and ferromagnetism for iron mixed-valence system, A[FeIIFeIII(C2O2S2)3] (A = (CnH2n+1)4N, (CmH2m+1)3(CnH2n+1)N)

    N. Kojima, N. Kida, A. Okazawa, M. Enomoto

    Mössbauer Effect Reference and Data Journal   35   154 - 165  2012年  [査読有り]  [招待有り]

  • Exchange coupling in TbCu and DyCu single-molecule magnets and related lanthanide and vanadium analogs

    Takayuki Ishida, Ryo Watanabe, Kei Fujiwara, Atsushi Okazawa, Norimichi Kojima, Go Tanaka, Shunsuke Yoshii, Hiroyuki Nojiri

    DALTON TRANSACTIONS   41 ( 44 ) 13609 - 13619  2012年  [査読有り]

     概要を見る

    Heterometallic coordination compounds [Cu-II(L)(C3H6O)Ln(III)(NO3)(3)] and [(VO)-O-IV(L)(C3H6O)Ln(III)(NO3)(3)] (abbreviated as LnCu and LnV, respectively; H2L = N,N'-bis(3-methoxysalicylidene)-1,3-diamino-2,2-dimethylpropane; Ln = Gd, Tb, Dy, Ho, and Er) were synthesized, and the X-ray crystallographic analysis shows that their structures are isomorphous for each series. The single-molecule magnet behavior was observed for TbCu and DyCu, and the activation energies of magnetization reversal were 42.3(4) and 11.5(10) K, respectively. The magnetic exchange couplings in LnCu and LnV were precisely evaluated by means of combined high-frequency EPR and pulsed-field magnetization studies, to give J(Tb-Cu)/k(B) &gt;= 3.3 K, J(Dy-Cu)/k(B) = 1.63(1) K, J(Ho-Cu)/k(B) = 1.09(2) K, and J(Er-Cu)/k(B) = 0.24(1) K. A monotonic decrease of ferromagnetic J(Ln-Cu) was found in the order of the atomic number, Gd-64 to Er-68. The corresponding exchange parameters in LnV are smaller than those of the Cu derivatives, and J(Gd-V) was antiferromagnetic (-3.0 K determined from the magnetization jump). A possible mechanism for the exchange coupling and chemical trend is discussed.

    DOI J-GLOBAL

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    70
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  • Ferromagnetic Exchange Couplings Showing a Chemical Trend in Cu-Ln-Cu Complexes (Ln = Gd, Tb, Dy, Ho, Er)

    Takashi Shimada, Atsushi Okazawa, Norimichi Kojima, Shunsuke Yoshii, Hiroyuki Nojiri, Takayuki Ishida

    INORGANIC CHEMISTRY   50 ( 21 ) 10555 - 10557  2011年11月  [査読有り]

     概要を見る

    Exchange couplings in isomorphous [LnCu(2)] were evaluated by high-frequency electron paramagnetic resonance and magnetization studies. The exchange parameter J(Ln-Cu) was decreased with an increase in the atomic, number; J(Ln-Cu)/k(B) = 4.45(11), 2.27(6), 0.902(10), 0.334(3), and 0.136(8) K for Ln = Gd, Tb, Dy, Ho, and Er, respectively.

    DOI PubMed CiNii

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    47
    被引用数
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  • Single-molecule magnet behavior enhanced by magnetic coupling between 4f and 3d spins

    Atsushi Okazawa, Hiroyuki Nojiri, Takayuki Ishida, Norimichi Kojima

    POLYHEDRON   30 ( 18 ) 3140 - 3144  2011年11月  [査読有り]

     概要を見る

    We synthesized and characterized a new compound [{Dy(hfac)(3)}(2)Pd(dpk)(2)] ([Dy(2)Pd]; Hdpk = di-2-pyridyl ketoxime), which is isostructural with the known [Dy(2)Cu] and [Dy(2)Ni]. The study of the [Dy(2)Pd] compound containing diamagnetic Pd ion is indispensable to clarify a contribution of the exchange coupling for a 4f-3d single-molecule magnet behavior. From the ac susceptibility measurements on [Dy(2)Pd], we obtained Delta/k(B) = 28.6(11) K and T(B) = 1.1 K. In accordance with the blocking behavior, the pulsed-field magnetization showed the hysteresis behavior below 1.1 K. These parameters on [Dy(2)Pd] having S(Pd) = 0 was compared with those of the derivatives having S(Cu) = 1/2 (Delta/k(B) = 47 K and T(B) = 1.8 K) and S(Ni) = 1 (Delta/k(B) = 62(4) K and T(B) = 2.5 K). The T(B) and Delta steadily increase with the increasing 3d(4d) spin quantum number. (C) 2011 Elsevier Ltd. All rights reserved.

    DOI

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    15
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  • Exchange couplings in one-dimensionally arrayed 4f–3d heterometallic [Ln2Cu2]n compounds: A chemical trend of the coupling parameter

    A. Okazawa, K. Fujiwara, R. Watanabe, N. Kojima, S. Yoshii, H. Nojiri, T. Ishida

    Polyhedron   30 ( 18 ) 3121 - 3126  2011年11月  [査読有り]

    DOI

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    21
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  • Study on the spin-crossover transition in [Fe(cis-/trans-stpy)(4)(X)(2)] (stpy: styrylpyridine, X: NCS, NCBH3) under high pressure toward ligand-driven light-induced spin change

    Akira Sugahara, Kimio Moriya, Masaya Enomoto, Atsushi Okazawa, Norimichi Kojima

    POLYHEDRON   30 ( 18 ) 3127 - 3130  2011年11月  [査読有り]

     概要を見る

    Toward the realization of a ligand-driven light-induced spin change (LD-LISC) around room temperature, we have investigated the spin-crossover phenomenon in [Fe(stpy)(4)(X)(2)] (stpy = styrylpyridine, X = NCS, NCBH3) under high pressure. The spin transition temperature increases from 110 to 220 K with increasing applied pressure up to 0.75 GPa for [Fe(trans-stpy)(4)(NCS)(2)], while [Fe(cis-stpy)(4)(NCS)(2)] shows the high-spin state in the temperature region between 2 and 300 K even at 0.75 GPa. In the case of X = NCBH3, due to the stronger ligand field of NCBH3, the spin transition temperature increases from 240 to 360 K with increasing applied pressure up to 0.50 GPa for [Fe(trans-stpy)(4)(NCBH3)(2)]. In the case of [Fe(cis-stpy)(4)(NCBH3)(2)], the spin state is the high-spin state in the temperature region between 2 and 300 K. However, the spin transition appears at 125 K under 0.5 GPa and the transition temperature increases with increasing applied pressure. In this way, we have decided the applied pressure region of 0.65-1.09 GPa where [Fe(stpy)(4)(NCBH3)(2)] undergoes LD-LISC at room temperature. (C) 2011 Elsevier Ltd. All rights reserved.

    DOI

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    10
    被引用数
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  • Development of pH-Sensitive Spin-crossover Iron(II) Complex Films, [Fe-II(diAMsar)]-Nafion: Manipulation of the Spin State by Proton Concentration

    Hajime Kamebuchi, Taketomo Jo, Hideharu Shimizu, Atsushi Okazawa, Masaya Enomoto, Norimichi Kojima

    CHEMISTRY LETTERS   40 ( 8 ) 888 - 889  2011年08月  [査読有り]

     概要を見る

    We newly synthesized transparent films composed of pH-sensitive spin-crossover complex [Fe-II(diAMsar)] (diAMsar: 1,8-diaminosarcophagine) and an ion-exchange polymer, Nafion, having different colors corresponding to proton concentration. The UV-vis spectroscopic measurements revealed that the films, which were provided under pH 4, 7, and 10 conditions, showed the spin state depending on pH.

    DOI J-GLOBAL

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    15
    被引用数
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  • Unusually Large Magnetic Anisotropy in a CuO-Based Semiconductor Cu5V2O10

    Zhangzhen He, Chensheng Lin, Wendan Cheng, Atsushi Okazawa, Norimichi Kojima, Jun-ichi Yamaura, Yutaka Ueda

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   133 ( 5 ) 1298 - 1300  2011年02月  [査読有り]

     概要を見る

    A CuO-based material Cu5V2O10 was successfully grown in a closed crucible using Sr(OH)(2)center dot 8H(2)O as flux. The structure of Cu5V2O10 can be viewed as being composed of two types of zigzag Cu-O chains running along the b- and c-axes, which shows a two-dimensional crosslike framework with 12-column square tunnels along the a-axis. Magnetic measurements show that Cu5V2O10 exhibits unexpected large magnetic anisotropy, which is the first time magnetic anisotropy energy of similar to 10(7) erg/cm(3) in the CuO-based materials has been observed. The origins of large anisotropy are suggested to arise from strong anisotropic exchanges due to the particular bonding geometry and the Jahn-Teller distortion of Cu2+ ions. Further, the band structure investigated by the GGA+U method suggests that Cu5V2O10 is a semiconductor.

    DOI PubMed

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    18
    被引用数
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  • Chemical trend of Ln-M exchange couplings in heterometallic complexes with Ln = Gd, Tb, Dy, Ho, Er and M = Cu, V

    Ryo Watanabe, Kei Fujiwara, Atsushi Okazawa, Go Tanaka, Shunsuke Yoshii, Hiroyuki Nojiri, Takayuki Ishida

    CHEMICAL COMMUNICATIONS   47 ( 7 ) 2110 - 2112  2011年  [査読有り]

     概要を見る

    The 4f-3d exchange couplings were definitively and precisely determined in the dinuclear complexes (Ln-M) involving double mu-oxo-bridges, by means of combined high-frequency electron paramagnetic resonance and pulsed-field magnetization techniques, revealing a monotonic decrease of ferromagnetic J(Ln-Cu) in the order of the atomic number, (64)Gd to (68)Er.

    DOI PubMed CiNii

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    47
    被引用数
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  • Ion-Induced Transformation of Magnetism in a Bimetallic CuFe Prussian Blue Analogue

    Masashi Okubo, Daisuke Asakura, Yoshifumi Mizuno, Tetsuichi Kudo, Haoshen Zhou, Atsushi Okazawa, Norimichi Kojima, Kazumichi Ikedo, Takashi Mizokawa, Itaru Honma

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   50 ( 28 ) 6269 - 6273  2011年  [査読有り]

    DOI PubMed

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    78
    被引用数
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  • Ferromagnetic Gd-Cu, Tb-Cu, and Ho-Cu Couplings in Isomorphous [Ln(2)Cu] Complexes

    Atsushi Okazawa, Ryo Watanabe, Masaru Nezu, Takashi Shimada, Shunsuke Yoshii, Hiroyuki Nojiri, Takayuki Ishida

    CHEMISTRY LETTERS   39 ( 12 ) 1331 - 1332  2010年12月  [査読有り]

     概要を見る

    Exchange couplings in [{Ln(hfac)(3)}(2)Cu(dpk)(2)] (Hdpk stands for di 2-pyridyl ketoxime) were evaluated by high-frequency electron paramagnetic resonance and magnetization studies, showing ferromagnetic Ln-Cu couplings with J(Ln-Cu)/k(B) = +1 271(7), +0 405(3), and +0 196(13) K for Ln Gd Tb, and Ho, respectively

    DOI J-GLOBAL

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    14
    被引用数
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  • Spin-Transition-Like Behavior on One Side in a Nitroxide-Copper(II)-Nitroxide Triad System

    Atsushi Okazawa, Takayuki Ishida

    INORGANIC CHEMISTRY   49 ( 21 ) 10144 - 10147  2010年11月  [査読有り]

     概要を見る

    The ground spin-state of [Cu(phpyNO)(2)(H(2)O)(2)](BF(4))(2) was switched between S(total) = 1/2 and 3/2 across 175 K. On warming, the space group was changed from P2(1)2(1)2(1) to C222(1) in a single-crystal-to-single-crystal manner, and the transient structure could be monitored by means of the crystallographic analysis. The copper-radical exchange coupling changed from 2J/k(B) = -463(3) to +312(6) K with rather small Cu-O-N-C(2py) twisting deformation on one side, while practically no distortion occurred on the other.

    DOI PubMed CiNii

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    42
    被引用数
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  • Ferro- and Antiferromagnetic Coupling Switch Accompanied by Twist Deformation around the Copper(II) and Nitroxide Coordination Bond

    Atsushi Okazawa, Daisuke Hashizume, Takayuki Ishida

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   132 ( 33 ) 11516 - 11524  2010年08月  [査読有り]

     概要を見る

    Two novel copper(II) complexes with tert-butyl 2-pyridyl nitroxide (2pyNO(center dot)), [Cu(2+)(2pyNO(-))(2PyNO(center dot))](2)(BF(4)(-))(2)(1 center dot BF(4)) and [Cu(2+)(2pyNO(-))(2pyNO(center dot))](2)(ClO(4)(-))(2)(1 center dot ClO(4)), were prepared and structurally characterized. They contained mixed-valent ligands from 2pyNO, whose oxygen atoms were located at equatorial positions of the copper ion. The [Cu(2+)(2pyNO(-))(2pyNO(center dot))] unit was dimerized by mu-oxo bridges of the anion ligand, giving a zigzag linear spin system involving four paramagnetic S = 1/2 centers. The two compounds are isomorphous in an orthorhombic Pbca space group. Magnetic study revealed that 1 center dot ClO(4) showed ferromagnetic copper-radical coupling in all temperature ranges investigated here. On the other hand, 1 center dot BF(4) exhibited a structural phase transition at 64 K, where the magnetic susceptibility was drastically dropped on cooling. The copper-radical magnetic couplings were characterized as ferro- and antiferromagnetic for the high- and low-temperature phases, respectively. The crystallographic analysis clarified that the nitroxide oxygen atom remained at the equatorial position throughout the single-crystal-to-single-crystal phase transition, while the previously known spin-transition-like copper-radical compounds showed conversion of the roles of equatorial and axial positions. The orthogonal arrangement between the copper d sigma and nitroxide pi(star) orbitals is essential for the ferromagnetic coupling, and a slight dislocation of the radical oxygen atom from the chelate plane leads to violation of the orthogonal orbital arrangement, giving a practically diamagnetic low-temperature phase.

    DOI PubMed CiNii

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    63
    被引用数
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  • Study on the Rapid Spin Equilibrium in Ph4P[ZnIIFeIII(mto)3] (mto = Monothiooxalato)

    Koichi Kagesawa, Atsushi Okazawa, Masaya Enomoto, Norimichi Kojima

    CHEMISTRY LETTERS   39 ( 8 ) 872 - 873  2010年08月  [査読有り]

     概要を見る

    We synthesized a mto (= monothiooxalato)-bridged heterometal complex, Ph4P[(ZnFeIII)-Fe-II(mto)(3))] consisting of (FeO3S3)-O-III and (ZnO6)-O-II octahedra and investigated its physical properties. Ph4P[(ZnFeIII)-Fe-II(mto)(3)] has a two-dimensional honeycomb network structure. The ESR and Fe-57 Mossbauer spectra revealed that the rapid spin equilibrium in which the high-spin (HS) state and the low-spin (LS) state exchange in the time scale of 10(-10) &lt; tau &lt; 10(-7)s occurs at the (FeO3S3)-O-III site, which is the first report for an assembled metal complex system.

    DOI J-GLOBAL

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    2
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  • 24
    被引用数
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  • Magnetic properties and exchange couplings of one-dimensionally arrayed 4f−3d heterometallic [Ln2Cu2]n compounds

    A. Okazawa, R. Watanabe, H. Nojiri, T. Nogami, T. Ishida

    Polyhedron   28 ( 9-10 ) 1808 - 1813  2009年06月  [査読有り]

    DOI

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    20
    被引用数
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  • Strong intramolecular ferromagnetic couplings in nickel(II) and copper(II) complexes chelated with tert-butyl 5-methoxy-2-pyridyl nitroxide

    Atsushi Okazawa, Takashi Nogami, Takayuki Ishida

    POLYHEDRON   28 ( 9-10 ) 1917 - 1921  2009年06月  [査読有り]

     概要を見る

    We successfully isolated a new paramagnetic bidentate ligand tert-butyl 5-methoxy-2-pyridyl nitroxide (meopyNO). Complexation of nickel(II) and copper(II) perchlorates with meopyNO gave the corresponding ML(2)-type bis-chelated compounds. The magnetic studies showed that they were ground high-spin molecules with 2J/k(B) = +288(5) and +178(3) K for [M(meopyNO)(2)(H(2)O)(2)]center dot(ClO(4))(2) (M = Ni and Cu, respectively), where the spin Hamiltonian is defined as H = -2J(S(1)center dot S(2) + S(2)center dot S(3)). From the crystallographic analysis, the torsion angles (phi) around M-O-N-C(2py) were 4.2(3)degrees and 6.87(19)degrees, respectively, being so small that the orthogonality between the magnetic radical pi* and the metal d sigma orbitals would be guaranteed. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI

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    23
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  • Ferromagnetic Dy-Ni and Antiferromagnetic Dy-Cu Couplings in Single-Molecule Magnets [Dy2Ni] and [Dy2Cu] (vol 47, pg 9763, 2008)

    Atsushi Okazawa, Takashi Nogami, Hiroyuki Nojiri, Takayuki Ishida

    INORGANIC CHEMISTRY   48 ( 7 ) 3292 - 3292  2009年04月  [査読有り]

     概要を見る

    &lt;B&gt;[Correction]&lt;/B&gt;

    DOI

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    21
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  • Ferromagnetic Dy-Ni and Antiferromagnetic Dy-Cu Couplings in Single-Molecule Magnets [Dy2Ni] and [Dy2Cu]

    Atsushi Okazawa, Takashi Nogami, Hiroyuki Nojiri, Takayuki Ishida

    INORGANIC CHEMISTRY   47 ( 21 ) 9763 - 9765  2008年11月  [査読有り]

     概要を見る

    The exchange couplings in [{Dy(hfac)(3)}(2)Cu(dpk)(2)] and [{Dy(hfac)(3)}(2)-Ni(dpk)(2)(py)(2)] (Hdpk = di-2-pyridyl ketoxime) were precisely evaluated by high-frequency electron paramagnetic resonance and pulsed-field magnetization studies, giving J(Dy-Cu)/k(B) = -0.126 K and J(Dy-Ni)/k(B) = +0.031 K.

    DOI PubMed CiNii

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    52
    被引用数
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  • Magneto-structure relationship in copper(II) and nickel(II) complexes chelated with stable tert-butyl 5-phenyl-2-pyridyl nitroxide and related radicals

    Atsushi Okazawa, Yasunori Nagaichi, Takashi Nogami, Takayuki Ishida

    INORGANIC CHEMISTRY   47 ( 19 ) 8859 - 8868  2008年10月  [査読有り]

     概要を見る

    We have isolated and characterized a new paramagnetic bidentate ligand, tert-butyl 5-phenyl-2-pyridyl nitroxide (phpyNO). The spin distribution onto the pyridine ring was clarified from the Electron Spin Resonance spectrum. Complexation of phpyNO with nickel(II) and copper(II) ions gave ML2-type chelated compounds. The magnetic measurements of [Ni(phpyNO)(2)(H2O)(2)]center dot(ClO4)(2) and [Cu(phpyNO)(2)(H2O)]center dot(ClO4)(2)center dot C6H4Cl2 revealed that the metalradical exchange couplings were ferromagnetic with 2J/k(B) = +409(10) and +434(12) K, respectively. The torsion angle (phi) around M-O-N-C-2py can be regarded as a reliable indicator for the plane geometry of chelates; namely, highly planar chelates defined by small phi exhibit ferromagnetic coupling. An approximate linear relation. was found in the J versus phi plot using the data of the present complexes and. related known compounds. The critical angle of phi, at which the sign of the metal-radical exchange changes from positive to negative, was 12.6(9)degrees. This finding could be almost reproduced by density-functional theory calculation on a model copper(II)-nitroxide dyad. The exchange couplings in equatorially coordinated copper(II)- and nickel(II)-nitroxide complexes are very strongly ferromagnetic by nature.

    DOI PubMed CiNii

    Scopus

    60
    被引用数
    (Scopus)
  • Exchange coupling and energy-level crossing in a magnetic chain [Dy2Cu2](n) evaluated by high-frequency electron paramagnetic resonance

    Atsushi Okazawa, Takashi Nogami, Hiroyuki Nojiri, Takayuki Ishida

    CHEMISTRY OF MATERIALS   20 ( 9 ) 3110 - 3119  2008年05月  [査読有り]

     概要を見る

    A 4f - 3d heterometallic polymeric coordination compound [[Dy(hfac)(2)(CH3OH)}(2)(Cu(dmg)(Hdmg)(2)}](n) [(Dy2Cu](n) Hdmg = dimethylglyoxime; Hhfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione) was synthesized, and the X-ray crystallographic analysis shows that the structure is isomorphous to the known ferrimagnetic [Gd2Cu2)](n) polymer. A centrosymmetric diamond-arrayed ferrimagnetic unit involving the oximate bridge, Dy - O - N - Cu, is repeated to form a discrete chain. An onset of the frequency dependence was found in the ac magnetic susceptibility measurements down to 1.8 K. Low-temperature magnetization measurements on [Dy2Cu2](n) exhibited magnetic hysteresis with magnetization steps. To examine the energy level structure and the exchange coupling between the Dy and Cu ions, high-frequency EPR (HF-EPR) spectra of a polycrystalline sample of [Dy2Cu2](n) were recorded at various frequencies (34.7 - 525.4 GHz) and temperatures. We analyzed the spectra by treating the Dy moments as Ising spins and built an exchange-coupling model for a diamond-arrayed tetranuclear macrocycle [Dy2Cu2]. The Dy - Cu exchange couplings were precisely evaluated, owing to the high resolution of HF-EPR; J/k(B) = - 0.895(8) and - 0.061(8) K for two independent Dy - Cu relations, where the exchange parameter is defined as - J. The Cu center dot center dot center dot Cu coupling among the macrocycles was estimated to be ferromagnetic with approximately 1 K. The present study has established the definitive methodology to examine the energy level in 4f - 3d heterometallic systems by using HF-EPR. The magnetic properties of the [Dy2Cu2](n) chain were plausibly described as a perturbed system of a single-molecule magnet. The quantum tunneling of the magnetization is based on a different principle compared with those of the 3d-based single-molecule magnets, since the energy level structure of [Dy2Cu2](n) is regulated by the exchange couplings.

    DOI CiNii

  • Tetranuclear heterometallic cycle Dy2Cu2 and the corresponding polymer showing slow relaxation of magnetization reorientation

    Sohei Ueki, Atsushi Okazawa, Takayuki Ishida, Takashi Nogami, Hiroyuki Nojiri

    POLYHEDRON   26 ( 9-11 ) 1970 - 1976  2007年06月  [査読有り]

     概要を見る

    We prepared tetranuclear complexes [{Cu(emg)(Hemg)(ROH)}(2)Dy(hfac)(2)(ROH)}(2)] (abbreviated as [Dy2Cu2]-R; R = Me, Et; H(2)emg=ethylmethylglyoxime) and the corresponding polymer [{Cu(dmg)(Hdmg)}(2){Dy(hfac)(2)(CH3OH)}(2)](n) center dot 2(MeOH) ([Dy2Cu2](n); H(2)dmg = dimethylglyoxime), which were characterized as analogs of the known [Gd2Cu2] monomer and polymer, respectively, by means of X-ray crystallographic analysis. The M-H curves clarified antiferromagnetic coupling between Dy and Cu in the [Dy2Cu2] motif, leading to the Dy magnetic moments aligned parallel ([Cu(down arrow)Dy(up arrow)Cu(down arrow)Dy(up arrow)]). Ac magnetic susceptibility measurements of [Dy2Cu2]-Me and [Dy2Cu2](n), exhibited a chi(ac)' (in-phase) decrease and a concomitant chi('')(ac) (out-of-phase) increase with an increase of frequency. Low-temperature magnetization measurements on [Dy2Cu2], exhibited magnetic hysteresis, which is characteristic of single-chain magnets. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    23
    被引用数
    (Scopus)
  • Preparation, structures, and magnetic properties of precursors for chelating compounds of 2-pyridyl nitroxide derivatives

    Atsushi Okazawa, Takashi Nogami, Takayuki Ishida

    POLYHEDRON   26 ( 9-11 ) 1965 - 1969  2007年06月  [査読有り]

     概要を見る

    We successfully synthesized and characterized two precursors for paramagnetic chelating ligands, N-p-anisyl-N-2-pyridylhydroxyl-amine and 2,6-bis(N-t-butylhydroxylamino)pyridine. The former can be regarded as a rare case since N,N-diarylhydroxylamines cannot be isolated in general because of facile autoxidation. The oxidation with silver(I) oxide gave radicals showing typical nitroxide ESR signals, but the resultant radicals were unstable under ambient conditions. Theoretical DFT calculation indicated that the bisnitroxide radical, pyridine-2,6-diyl bis(t-butyl nitroxide), had a triplet ground state. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • tert-Butyl 2-Pyridyl Nitroxide Available as a Paramagnetic Chelate Ligand for Strongly Exchange-Couples Metal−Radical Compounds

    A. Okazawa, T. Nogami, T. Ishida

    Chemistry of Materials   19 ( 11 ) 2733 - 2735  2007年05月  [査読有り]

    DOI CiNii

    Scopus

    38
    被引用数
    (Scopus)
  • Strong ferromagnetic exchange couplings in copper(II) and nickel(II) complexes with a paramagnetic tridentate chelate ligand, 2,2 '-bipyridin-6-yl tert-butyl nitroxide

    Keita Osanai, Atsushi Okazawa, Takashi Nogami, Takayuki Ishida

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   128 ( 43 ) 14008 - 14009  2006年11月  [査読有り]

    DOI PubMed CiNii

    Scopus

    70
    被引用数
    (Scopus)
  • Ferromagnetic exchange coupling in a spiro-fused dinuclear nickel(II) complex with an approximate D-2d symmetry

    Atsushi Okazawa, Takashi Nogami, Takayuki Ishida

    CHEMICAL PHYSICS LETTERS   427 ( 4-6 ) 333 - 337  2006年08月  [査読有り]

     概要を見る

    Ferromagnetic exchange coupling was operative between nickel(II) spins in a dinuclear nickel(II) complex [{Ni(hfac)(2)}(2)(py(4)C)] with J/k(B) = +0.57(2)K (H = -2JS(1) . S-2), where hfac and py(4)C Stand for 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and tetrakis(2-pyridyl)methane, respectively. X-ray crystal structure analysis revealed an approximate D-2d symmetry of the [Ni(py4C)Ni] core and accordingly the orthogonal arrangement between the two coordination basal planes. Mechanism of the ferromagnetic coupling was proposed on the basis of the orthogonal d sigma-type magnetic orbitals, which was supported by DFT calculation. (c) 2006 Elsevier B.V. All rights reserved.

    DOI CiNii

    Scopus

    11
    被引用数
    (Scopus)
  • Structures and magnetic properties of copper(II) complexes containing tetrakis(2-pyridyl)methane

    A Okazawa, T Ishida, T Nogami

    POLYHEDRON   24 ( 16-17 ) 2584 - 2587  2005年11月  [査読有り]

     概要を見る

    We designed spiro-fused dinculear complexes using tetrakis(2-pyridyl)methane (py(4)C) for the development of ground high-spin molecules. We attempted to prepare a dinuclear copper(II) complex [{Cu(hfac)(2)}(2)(py(4)C)], where hfac stands for 1, 1,1,5,5,5-hexafluoropentane-2,4-dionate, but we obtained [Cu(hfac)(2)(py(4)C)] and [Cu(hfac)(py(4)C) (.) Cu(hfac)(3)]. These molecular structures were determined by the X-ray crystal structure analysis. (c) 2005 Elsevier Ltd. All rights reserved.

    DOI J-GLOBAL

    Scopus

    15
    被引用数
    (Scopus)
  • Dinuclear manganese(II) complex containing tetrakis(2-pyridyl)methane as a spiro-fused bridge

    A Okazawa, T Ishida, T Nogami

    CHEMISTRY LETTERS   33 ( 11 ) 1478 - 1479  2004年11月  [査読有り]

     概要を見る

    A dinuclear manganese(II) complex [{Mn(hfac)(2)}(2)(py(4)C)] was synthesized, where hfac and py(4)C denote 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and tetrakis(2-pyridyl)methane, respectively. X-Ray crystallographic analysis revealed that the dihedral angle was 87.4(2)degrees between two chelate rings around the spiro center. Very weak antiferromagnetic interaction is operative between manganese(II) spins.

    DOI CiNii

    Scopus

    17
    被引用数
    (Scopus)

▼全件表示

書籍等出版物

  • Modern Mössbauer Spectroscopy : New Challenges Based on Cutting-Edge Techniques

    Yoshida, Yutaka, Langouche, Guido

    Springer  2021年 ISBN: 9789811594212

  • 錯体化合物事典

    錯体化学会

    朝倉書店  2019年 ISBN: 9784254141054

Misc

  • スピン平衡を示す鉄(II)錯体のメスバウアー分光およびミュオン分光からみた動的挙動

    小林弘明, 岡澤厚, 川崎郁斗, 渡邊功雄, 小島憲道

    KURRI KR   ( 195 ) 23 - 26  2014年03月

    J-GLOBAL

  • 直線型二配位鉄錯体のメスバウアー分光研究(III)

    小林義男, 松尾司, 伊藤幹直, 長友傑, 中村仁, 森雅樹, 岡澤厚, 小島憲道, 玉尾皓平

    KURRI KR   ( 168 ) 57 - 60  2012年02月

    J-GLOBAL

  • ベルダジルラジカルが配位した新奇鉄(II)錯体[FeII(vdco)2(H2O)2]・2H2Oの結晶構造と物性:水分子の配向挙動に起因する57Feメスバウアースペクトルの異常な振舞いの解明

    亀渕萌, 岡澤厚, 榎本真哉, 原田潤, 小川桂一郎, 大久保將史, 丸田悟朗, 武田定, 小島憲道

    KURRI KR   ( 168 ) 51 - 56  2012年02月

    J-GLOBAL

  • (C6H5)4P[Mn(II)Fe(III)(mto)3](mto=C2O3S)における速いスピン平衡と多段階磁気相転移の協奏現象

    影澤幸一, 岡澤厚, 榎本真哉, 小島憲道

    KURRI KR   ( 159 ) 53 - 58  2011年02月

    J-GLOBAL

  • 鉄混合原子価錯体(n‐CnH2n+1)4N[FeIIFeIII(mto)3](n=3,4;mto=C2O3S)における速いスピン平衡と電荷揺動の協奏現象

    影澤幸一, 岡澤厚, 榎本真哉, 小島憲道

    KURRI KR   ( 152 ) 19 - 22  2010年03月

    J-GLOBAL

  • 27aQJ-11 RE-3dヘテロ金属分子磁性体の交換相互作用と磁性(量子スピン系(二次元系及びその他),領域3,磁性,磁気共鳴)

    野尻 浩之, 林 美咲, 田中 豪, 吉居 俊輔, Gomella A., 石田 尚行, 岡澤 厚

    日本物理学会講演概要集   64 ( 2 ) 368 - 368  2009年08月

    CiNii

  • HF‐EPR測定を用いた希土類イオン―遷移金属イオン間の交換相互作用定数の決定

    岡澤厚

    電子スピンサイエンス   ( 10 ) 41 - 42  2008年03月

    J-GLOBAL

▼全件表示

受賞

  • 第3回新化学技術研究奨励賞

    2014年05月   公益社団法人新化学技術推進協会   希土類フリーな硬質分子磁石の創製を目指した基盤的研究  

    受賞者: 岡澤 厚

  • 日本化学会第93春季年会優秀講演賞(学術)

    2013年03月   公益社団法人日本化学会   ランタノイド(III)―ニッケル(II)ヘテロスピン系における交換相互作用と分子構造の化学的傾向  

    受賞者: 岡澤 厚

  • 第26回井上研究奨励賞

    2009年12月   財団法人井上科学振興財団   4f-3d,3d-3dおよび3d-2pスピンを有する磁性材料における分子構造と交換相互作用の相関についての研究  

  • 日本化学会第89春季年会学生講演賞

    2009年04月   社団法人日本化学会   4f-3dヘテロスピン系錯体におけるランタノイドイオン種と交換相互作用との相関  

  • 電子スピンサイエンス国際学会-第46回電子スピンサイエンス学会年会合同討論会(ISESS-SEST2007)優秀発表賞

    2007年11月   電子スピンサイエンス学会   Exchange Coupling and Energy-Level Structure of 4f3d Single-Molecule Magnets Determined by High-Frequency EPR  

  • ICMM2006 Poster Prize

    2006年08月   The 10th International Conference on Molecule-based Magnets (ICMM2006)   Preparation, Structures, and Magnetic Properties of Chelating Compounds of 2-Pyridyl Nitroxide Derivatives  

▼全件表示

共同研究・競争的資金等の研究課題

  • マルチサイトなラジカルキレート配位子の開発とフェリ磁性体の構築

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    研究期間:

    2018年04月
    -
    2021年03月
     

    岡澤 厚

     概要を見る

    極限に強い磁気結合力を有し、ラジカル―金属錯体系の構造と磁性のシンプルな相関性が見出されてきた「ラジカルキレート配位子」の展開として、マルチサイトなラジカルキレート配位子の新規開発を目標として、平成30年度は二箇所でラジカルキレート配位が可能な「デュアルラジカルキレート配位子」の開発を推進した。
    「三座+二座」キレート可能なビラジカル配位子をクレーンケピリジン合成法によって構築することを試みた。市販の原料から3ステップで、ターピリジン骨格の構築に成功した。この化合物は、互変異性としてピリドン体で単離されている。連結位置の複雑なターピリジン骨格の形成に、クレーンケピリジン合成法が有用であることを示すことができた。今後は、ヒドロキシル基をブロモ化し、続いてヒドロキシル基に変換して酸化剤でラジカル化することで目的のビラジカル配位子を得る。当該年度の目標としていた目的とするビラジカル配位子の合成は未達成であるが、途中段階のピリドン体で思いがけず溶液中で発光性を有するものが得られた。粉末は紫色であるが、溶媒の極性に応じて緑~青色溶液に呈色するソルバトクロミズムを示した。また、Znイオンを共存させると紫外線照射で強く発光する。今後、特定のイオンを認識するセンサー材料などへの発展も期待される。
    また、当該年度はこれまでの研究成果として「デュアルラジカルキレート配位子」の元となったラジカルキレート配位子の論文化を進め、英国化学会の国際学術誌のひとつであるNew Journal of Chemistryに投稿し受理された。研究内容が評価され、当該学術誌のバックカバー絵に選出された。

  • 低次元応力場によるギミックで創出するメカノマグネティック材料

    公益財団法人池谷科学技術振興財団  2020年度単年度研究助成

    研究期間:

    2020年04月
    -
    2021年03月
     

  • 低温化学溶液還元によって酸化物中の遷移金属元素の価数を制御する

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    研究期間:

    2017年04月
    -
    2020年03月
     

    井上 亮太郎, 岡澤 厚

     概要を見る

    平成29年度に、酸化物LiNbO3中にある遷移金属元素Feの価数を低温化学溶液還元によって制御することに成功した。これは当初の予定通りであった。その過程で予想していなかった実験結果を得て、その原因を考えることによって、還元の制御機構について新しい物理的モデルの確立に成功した。このため、研究計画を前倒しして平成30年度前半にこの物理的モデルについて論文を投稿する予定を立てたが、データ解析の定量性に問題が生じ、平成30年度内に論文を投稿できなかった。問題解決のめどはある程度たったので、平成31年度前半には投稿したいと考えている。
    論文執筆作業と並行して平成30年度後半では、低温化学溶液還元技術の更なる開発を行った。具体的にはLiNbO3に加えてBiFeO3やBaTiO3粉末を準備し、低温化学溶液還元によってドープしたFeやMnなどの遷移金属元素の価数制御を試みた。どの粉末においても還元には成功したが、まだ系統的な実験結果を得るに至っていない。M&ouml;ssbauer分光測定に必要なCo線源の強度が研究開始当初の予想よりも落ちてきているため、今後はESR(電子スピン共鳴)測定なども併用して遷移金属元素の価数決定を行うことを考えている。
    平成31年度からは、還元機構のさらなる解明に向けて、遷移金属二元酸化物の還元をも試みる。合わせて酸化物強誘電体の光電変換機能増強や酸化物高温超伝導体の超伝導転移温度制御などのデモンストレーションを行い、研究をまとめる。

  • 動的スピン平衡によるスピンフラストレーション及び連鎖する特異な磁気秩序の開拓

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    研究期間:

    2016年04月
    -
    2019年03月
     

    小島 憲道, 岡澤 厚, 榎本 真哉

     概要を見る

    集積型金属錯体(C6H5)4P[Mn(II)Fe(III)(C2O3S)3]を開発し、Mn(II)とFe(III)間の磁気相互作用がFe(III)の動的スピン平衡のため0.1 μsより速い時間で強磁性相互作用と反強磁性相互作用が交互に働き、この動的スピン平衡と連鎖する磁気相互作用のフラストレーションのため、この系は2段階の特異な磁気相転移を起こすことを明らかにした。30 Kで起こる磁気相転移では、Mn(II)スピンのみ磁気整列し、23 Kで起こる2段階目の磁気相転移でMn(II)スピンとFe(III)スピンがともに磁気整列することを磁気測定および57Feメスバウアー分光法で明らかにした。

  • 室温分子磁石を目指したマルチラジカル配位子の開発と多核高スピン錯体の構築

    文部科学省  科学研究費補助金(若手研究(B))

    研究期間:

    2015年
    -
    2016年
     

    岡澤 厚

  • 希土類フリーな硬質分子磁石の創製を目指した基盤的研究

    公益社団法人新化学技術推進協会  第3回新化学技術研究奨励賞

    研究期間:

    2014年07月
    -
    2015年03月
     

    岡澤 厚

  • 複合機能性材料を目指した超分子磁性体の開発

    文部科学省  科学研究費補助金(基盤研究(C))

    研究期間:

    2007年
    -
    2009年
     

    石田尚行, 岡澤厚

     概要を見る

    本研究では有機無機ハイブリッド分子性磁性体を中心に複合機能の開発を進めた。(1)機能性低次元磁石:ラジカル-コバルト系単一次元鎖磁石からこれまでの世界最高の保磁力をもつ磁性材料を開発した。(2)分子包接誘起磁性体:ラジカル置換のホスト・配位子分子を構築し、その磁性を超分子化学手法により制御した。(3)液晶性磁石・可溶化磁石:長鎖アルキル基を有する鉄(II)錯体を合成し、中間相転移とスピン転移の共存する系を得た。

  • 希土類-遷移金属複合錯体における単分子磁石挙動の系統的理解とその発展的改良

    文部科学省  科学研究費補助金(若手研究(B))

    岡澤厚

     概要を見る

    本研究では、究極的な分子サイズ磁気メモリの候補である「単分子磁石」について、新規な希土類―遷移金属複合錯体を開発し、磁気結合力の解明を行った。三核錯体[DyMDy] (M = Pd, Cu, Ni)で、遷移金属イオンのスピン数が大きくなるにつれ単分子磁石性能が向上することを明らかにした。さらに、最も性能の良い[DyNiDy]錯体では、アキシャル配位子をメチルイミダゾールにした物質で単分子性能の向上が見られ、Dy周りの配位環境の違いによることを見出した。その他、[LnCu]、[LnV]、[CuLnCu]、[Ln4Cu]、[Ln2Cu2]n型錯体に対する磁気結合力の化学的傾向も明らかにした。

▼全件表示

講演・口頭発表等

  • 結晶構造解析とDFT計算による鉄混合原子価錯体(n-C3H7)4N[FeIIFeIII(dto)3]の光誘起電荷移動相転移の可能性の検討

    糸井 充穂, 岡澤 厚, 山浦 淳一, 真木 祥千子, 小松 徳太郎, Isabelle Maurin, Epiphane Codjovi, Kamel Boukheddaden, 小島 憲道

    日本物理学会第74回年次大会   (九州大学伊都キャンパス(福岡県福岡市)) 

    発表年月: 2019年03月

  • ジアリールコバト二価錯体の合成と反応

    管野 公平, 岡澤 厚, 松尾 司

    日本化学会第99春季年会   (甲南大学岡本キャンパス(兵庫県神戸市)) 

    発表年月: 2019年03月

  • Spin dynamics in tripyrazolylmethane iron(II) complexes showing static and dynamic spin-crossover phenomena

    A. Okazawa, H. Kobayashi, I. Kawasaki, I. Watanabe, N. Kojima

    The 9th TOYOTA RIKEN International Workshop on New Developments and Prospects for Futrue of Mössbauer Spectroscopy (IWMS2018)   (Toyota Commemorative Museum of Industry and Technology (Nagoya, Japan)) 

    発表年月: 2018年11月

  • Comparison of μSR Spectra for Tripyrazolylmethane Iron(II) Spin-Crossover Complexes to Investigate Spin Dynamics

    A. Okazawa, H. Kobayashi, I. Watanabe, I. Kawasaki, N. Kojima

    2nd RIKEN SyMPOSIUM   (Prama Sanur Beach Bali Hotel (Bali, Indonesia)) 

    発表年月: 2018年11月

  • Magneto-Structural Relationship on Metal Complexes Using Dual Radical Chelate Ligand Showing Ground Triplet State

    A. Okazawa, T. Ishida, N. Kojima

    43rd International Conference on Coodination Chemistry (ICCC2018)   (Sendai International Conference Center (Sendai, Japan)) 

    発表年月: 2018年08月

  • Crystal structure construction of organic salts comprising proton, H+, as a counter cation

    R. Tanaka, A. Okazawa, N. Kojima, N. Matsushita

    日本化学会第98春季年会  

    発表年月: 2018年03月

  • ジチオオキサラト架橋ヘテロ金属錯体の光照射下での磁気挙動

    永峰 翔太, 榎本 真哉, 岡澤 厚

    日本化学会第98春季年会   (日本大学理工学部船橋キャンパス(千葉県船橋市)) 

    発表年月: 2018年03月

  • ターピリジン誘導体を配位子とするIr錯体の光水素発生反応における増感特性

    加藤 天, 生田 直也, 岡澤 厚, 滝沢 進也, 村田 滋

    日本化学会第98春季年会   (日本大学理工学部船橋キャンパス(千葉県船橋市)) 

    発表年月: 2018年03月

  • クマリン誘導体を配位子とするイリジウム錯体の合成と光増感一重項酸素発生への応用

    宮岸 優奈, 生田 直也, 岡澤 厚, 滝沢 進也, 村田 滋

    日本化学会第98春季年会   (日本大学理工学部船橋キャンパス(千葉県船橋市)) 

    発表年月: 2018年03月

  • バナジウム希釈系混合原子価鉄錯体(n-C3H)4N[FeIIFeIII1-xVIIIx(C2O2S2)3]の誘電測定による電荷移動挙動の検出

    川本 史仁, 志田 典浩, 岡澤 厚, 小島 憲道, 榎本 真哉

    日本化学会第98春季年会   (日本大学理工学部船橋キャンパス(千葉県船橋市)) 

    発表年月: 2018年03月

  • 基底三重項を示すデュアルラジカキレート配位子用いた金属錯体の合成、構造および磁性

    岡澤 厚, 石田 尚行, 小川 桂一郎, 小島 憲道

    錯体化学会第67回討論会   (北海道大学札幌キャンパス(北海道札幌市)) 

    発表年月: 2017年09月

  • Syntheses and Magnetic Properties of Linear Two-Coordinated Iron(II) and Iron(I) Complexes

    A. Okazawa, T. Matsuo, Y. Kobayashi  [招待有り]

    International Conference on the Applications of the Mössbauer Effect (ICAME2017)   (Azimut Hotel (Saint-Petersburg, Russia)) 

    発表年月: 2017年09月

  • Enhanced Magnetism of Perovskite Oxides, Sr(Sn,Fe)O3-δ, by Substitution of Non-Magnetic Ca and Ti ions

    K. Nomura, S. Suzuki, T. Mizunuma, Y. Koike, A. Okazawa

    International Conference on the Applications of the Mössbauer Effect (ICAME2017)   (Azimut Hotel (Saint-Petersburg, Russia)) 

    発表年月: 2017年09月

  • 57Fe and 119Sn Mossbauer Study of SrSnO3 Doped with Fe and Sb

    K. Nomura, S. Suzuki, Y. Koike, A. Okazawa, Y. Kobayashi, M. Kaneko

    International Conference on the Applications of the Mössbauer Effect (ICAME2017)   (Azimut Hotel (Saint-Petersburg, Russia)) 

    発表年月: 2017年09月

  • Control of Charge Transfer Phase Transition and Ferromagnetism for Iron Mixed-valence Complexes by Means of Photo-isomerization

    N. Kojima, J. Yoshida, A. Okazawa, M. Enomoto, Y. Kobayashi

    International Conference on the Applications of the Mössbauer Effect (ICAME2017)   (Azimut Hotel (Saint-Petersburg, Russia)) 

    発表年月: 2017年09月

  • Rind配位子を用いた直線二配位鉄(I)錯体の動的スピン挙動

    岡澤 厚, 二階 正憲, 羽村 将宏, 合田 舜, 早川 直輝, 松尾 司

    日本化学会第97春季年会   (慶應義塾大学日吉キャンパス(神奈川県横浜市)) 

    発表年月: 2017年03月

  • CaおよびTiの置換によるSr(Sn,Fe)O3の磁気特性とMössbauerスペクトル

    水沼 丈也, 鈴木 茂世, 小池 裕也, 野村 貴美, 岡澤 厚

    第18回メスバウアー分光研究会シンポジウム   (東京理科大学森戸記念館(東京都新宿区)) 

    発表年月: 2017年03月

  • ビピリジン骨格を有する有機アクセプター分子と鉄錯体ドナーからなるベイポクロミック電荷移動塩における構造未知相の粉末X線構造解析

    田中 李叶子, 小中 尚, 佐々木 明登, 岡澤 厚, 小島 憲道, 松下信之

    日本結晶学会平成28年度年会   (茨城県立県民文化センター(茨城県水戸市)) 

    発表年月: 2016年11月

  • Magneto-Structural Relationship on Strong Exchange Interactions between Chelating Radical and Transition-Metal Spins

    A. Okazawa  [招待有り]

    The 4th International Conference on Advanced Materials Science and Technology (ICAMST2016)   (Universitas Negeri Malang (Malang, Indonesia)) 

    発表年月: 2016年09月

  • ビピリジン骨格を有する有機アクセプターと鉄錯体ドナーからなる電荷移動塩における固相合成相の結晶構造

    田中 李叶子, 岡澤 厚, 小島 憲道, 松下 信之

    第25回有機結晶シンポジウム   (京都大学吉田南キャンパス(京都府京都市)) 

    発表年月: 2016年09月

  • 鎖状二価カチオンがもたらす鉄混合原子価錯体における磁性層の歪みによる電荷移動挙動の変化

    矢口 寛, 佐々木 翔太郎, 榎本 真哉, 岡澤 厚, 小島 憲道

    錯体化学会第66回討論会   (福岡大学七隈キャンパス(福岡県福岡市)) 

    発表年月: 2016年09月

  • ベイポクロミック鉄錯体電荷移動塩の粉末X線構造解析による結晶構造解明

    田中 李叶子, 小中 尚, 佐々木 明登, 岡澤 厚, 小島 憲道, 松下信之

    錯体化学会第66回討論会   (福岡大学七隈キャンパス(福岡県福岡市)) 

    発表年月: 2016年09月

  • Magnetic Properties of V-Substitution Effect in an Iron Mixed Valence Complex

    N. Shida, Y. Suzawa, A. Okazawa, N. Kojima, M. Enomoto

    The 15th International Conference on Molecule-based Magnets (ICMM2016)   (Sendai International Center (Sendai, Japan)) 

    発表年月: 2016年09月

  • The ChargeTransfer Phase Transition In An Iron-Mixed Valence Complex With Specific π-Conjugated Cations As Intercalants

    M. Enomoto, M. Shirakawa, H. Izawa, K. Sato, A. Okazawa, N. Kojima

    The 15th International Conference on Molecule-based Magnets (ICMM2016)   (Sendai International Center (Sendai, Japan)) 

    発表年月: 2016年09月

  • Syntheses, Crystal Structures, and Magnetic Properties of Copper(II) Complexes with Bischelate and High-Spin Biradical Ligand

    A. Okazawa, T. Ishida, K. Ogawa, N. Kojima

    The 15th International Conference on Molecule-based Magnets (ICMM2016)   (Sendai International Center (Sendai, Japan)) 

    発表年月: 2016年09月

  • [Dy2Ni]型錯体における単分子磁石挙動とスピンエネルギーダイアグラム

    岡澤 厚, 野尻 浩之, 石田 尚行, 小島 憲道

    日本化学会第96春季年会  

    発表年月: 2016年03月

  • Magnetic Properties of V-Substitution Effect in an Iron Mixed Valence Complex

    SHIDA, Norihiro, SUZAWA, Yoshiki, INABA, Michikazu, OKAZAWA, Atsushi, KOJIMA, Norimichi, ENOMOTO, Masaya

    日本化学会第96春季年会  

    発表年月: 2016年03月

  • デカメチルメタロセニウムを挿入した鉄混合原子価錯体の合成と物性評価

    大橋 奈実, 井田 博道, 岡澤 厚, 小島 憲道, 榎本 真哉

    日本化学会第96春季年会  

    発表年月: 2016年03月

  • Pressure dependence of a ferromagnetic transition for cobalt layered hydroxides with diarylethene derivatives

    Yu Inada, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    日本化学会第96春季年会  

    発表年月: 2016年03月

  • 鉄置換ニオブ酸リチウム系強誘電体薄膜の可視光起電力評価

    高橋秀輔, 井上亮太郎, 松尾拓紀, 岡澤厚, 小島憲道, 石垣徹, 吉田幸彦, 野口祐二, 宮山勝

    第54回セラミックス基礎科学討論会  

    発表年月: 2016年01月

  • Proton-responsive emission properties in cyclometalated iridium(III) complex film, [IrIII(bdp)3]@Nafion (bdp = 2,4’-(benzene-1,3-diyl)dipyridine)

    Hajime Kamebuchi, Yu Fujimura, Atsushi Okazawa, Makoto Tadokoro, Norimichi Kojima

    The International Chemical Congress of Pacific Basin Societies 2015 (Pacifichem2015)  

    発表年月: 2015年12月

  • Effect on the ferromagnetic transition temperature of the cobalt layered hydroxides by employment of the monovalent diarylethene derivative with a carboxyl group

    Yu Inada, Shoko Kubota, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    The International Chemical Congress of Pacific Basin Societies 2015 (Pacifichem2015)  

    発表年月: 2015年12月

  • Syntheses and magnetic properties of transition-metal complexes with multichelating and high-spin radical ligands

    Atsushi Okazawa, Takayuki Ishida, Norimichi Kojima, Keiichiro Ogawa

    The International Chemical Congress of Pacific Basin Societies 2015 (Pacifichem2015)  

    発表年月: 2015年12月

  • Correlation between charge transfer on a magnetic layer of the iron mixed valence complex and molecular polarization of cationic intecalants

    Kazuma Arai, Hiromichi Ida, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    The International Chemical Congress of Pacific Basin Societies 2015 (Pacifichem2015)  

    発表年月: 2015年12月

  • Development of dilute magnetic materials - magnetic property and Mossbauer spectra of SrSnO3 doped with Fe and Sb

    Shigeyo Suzuki, Yuya Koike, Kiyoshi Nomura, Atsushi Okazawa, Norimichi Kojima

    The International Chemical Congress of Pacific Basin Societies 2015 (Pacifichem2015)  

    発表年月: 2015年12月

  • ジヒドロビピリジニウムと鉄錯体からなる電荷移動塩の酸蒸気によるベイポクロミズム

    田中 李叶子, 岡澤 厚, 小島 憲道, 松下 信之

    第24回有機結晶シンポジウム  

    発表年月: 2015年11月

  • 鉄置換ニオブ酸リチウム系強誘電体薄膜の光起電力特性

    高橋秀輔, 井上亮太郎, 松尾拓, 岡澤 厚, 小島憲道, 石垣 徹, 吉田幸彦, 野口祐二, 宮山 勝

    第 35 回エレクトロセラミックス研究討論会  

    発表年月: 2015年10月

  • 環状ジカチオンを挿入した鉄混合原子価錯体における磁性層の歪みと電荷移動挙動の変化

    須澤 嘉紀, 佐々木 翔太郎, 井田 博道, 榎本 真哉, 嶋田 紅葉, 横田 香織, 秋田 素子, 岡澤 厚, 小島 憲道

    錯体化学会第65回討論会  

    発表年月: 2015年09月

  • モノカルボン酸型ジアリールエテン誘導体を挿入したコバルト層状磁性体の磁気挙動変化

    稲田 雄, 久保田 尚子, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第65回討論会  

    発表年月: 2015年09月

  • 直線型二配位構造を有する有機鉄錯体の合成と物性

    松尾 司, 合田 舜, 伊藤幹直, 橋爪大輔, 玉尾皓平, 岡澤 厚, 小島憲道, 小林義男, 笛野博之, 田中一義

    第62回有機金属化学討論会  

    発表年月: 2015年09月

  • 陽イオン交換膜Nafionに担持されたシクロメタレート型イリジウム(III)錯体のpHに依存した発光特性

    藤村 有生, 亀渕 萌, 岡澤 厚, 小島 憲道

    日本化学会第95春季年会  

    発表年月: 2015年03月

  • かさ高いRind基を有する有機鉄二価錯体の還元反応

    合田 舜, 岡澤 厚, 小島 憲道, 橋爪 大輔, 小林 義男, 田中 一義, 笛野 博之, 松尾 司

    日本化学会第95春季年会  

    発表年月: 2015年03月

  • 基底高スピンかつマルチなキレート部位を有するビラジカル配位子およびその遷移金属錯体の合成と磁性

    岡澤 厚, 小島 憲道

    日本化学会第95春季年会  

    発表年月: 2015年03月

  • ヘキサシアニド鉄(II)錯体電荷移動塩の酸蒸気による二段階ベイポクロミズムにおける橙色相の解明

    田中 李叶子, 岡澤 厚, 小島 憲道, 松下 信之

    日本化学会第95春季年会  

    発表年月: 2015年03月

  • アニオン部位の異なるジアリールエテン誘導体を挿入したコバルト層状磁性体の磁気挙動変化

    稲田 雄, 久保田 尚子, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • モノチオシュウ酸架橋層状ヘテロ金属錯体のスピン平衡に対する金属置換効果

    深尾 陽一, 影澤 幸一, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • 2価カチオンのアルキル鎖長がもたらす層状鉄混合原子価錯体における電荷移動挙動の変化

    佐々木 翔太郎, 井田 博道, 榎本 真哉, 岡澤 厚, 小島 憲道

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • ジアリールエテン誘導体を挿入したコバルト層状水酸化物における層間π共役系の磁性への寄与

    久保田 尚子, 大島 祐史, 榎本 真哉, 岡澤 厚, 小島 憲道

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • pH応答発光性イリジウム(III)錯体膜の開発

    亀渕 萌, 岡澤 厚, 小島 憲道

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • 直線型二配位構造を有する有機鉄二核錯体の合成と物性

    合田 舜, 岡澤 厚, 小島 憲道, 橋爪 大輔, 小林 義男, 田中 一義, 笛野 博之, 松尾 司

    錯体化学会第64回討論会  

    発表年月: 2014年09月

  • The distortional effect on the magnetic layer of the iron mixed valence complex due to introduction of divalent cationic intercalants

    Shotaro Sasaki, Hiromichi Ida, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    The 14th International Conference on Molecule-Based Magnets (ICMM2014)  

    発表年月: 2014年07月

  • Control of ferromagnetic transition temperature in a cobalt layered magnet with a carboxylated diarylethene derivative as an intercalant

    Yu Inada, Shoko Kubota, Atsushi Okazawa, Norimichi Kojima, Masaya Enomoto

    The 14th International Conference on Molecule-Based Magnets (ICMM2014)  

    発表年月: 2014年07月

  • Study on the Static and Dynamic Spin-crossover Phenomena in Tripyrazolylmethane Iron(II) Complexes by Muon Spectroscopy

    H. Kobayashi, A. Okazawa, I. Kawasaki, I. Watanabe, N. Kojima

    The 14th International Conference on Molecule-Based Magnets (ICMM2014)  

    発表年月: 2014年07月

  • Magnetic Switching by Photo-irradiation in the Spin-crossover Iron(III) Complex with Photoisomerizable Counteranion

    H. Kamebuchi, A. Sugahara, A. Okazawa, N. Kojima

    The 14th International Conference on Molecule-Based Magnets (ICMM2014)  

    発表年月: 2014年07月

  • 4f-3dヘテロスピン系錯体における単分子磁石性能および交換相互作用の化学的傾向

    岡澤 厚, 吉居 俊輔, 野尻 浩之, 石田 尚行, 小島 憲道  [招待有り]

    第1回東北大学リーディング大学院研究会  

    発表年月: 2014年04月

  • シュウ酸およびジチオシュウ酸に架橋された新奇二核鉄錯体の合成と物性

    坂口 岳志, 井田 博道, 岡澤 厚, 小島 憲道, 榎本 真哉

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • モノチオオキサレート架橋ヘテロ金属錯体におけるスピン平衡と電荷移動相転移

    深尾 陽一, 影澤 幸一, 岡澤 厚, 小島 憲道, 榎本 真哉

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • カルボン酸部位を有するジアリールエテン誘導体を挿入したコバルト層状磁性体のπ共役系スイッチを利用した強磁性転移温度の制御

    稲田 雄, 久保田 尚子, 岡澤 厚, 小島 憲道, 榎本 真哉

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • pHに依存した発光特性を示すRu(II)錯体膜の開発と発光挙動の制御

    玉樹 怜, 亀渕 萌, 岡澤 厚, 小島 憲道

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • 直線型二配位構造を有する有機鉄二価二核錯体の合成と物性

    合田 舜, 岡澤 厚, 小島 憲道, 橋爪 大輔, 小林 義男, 笛野 博之, 田中 一義, 松尾 司

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • 鉄(II)スピンクロスオーバー錯体における動的スピン平衡のμSR法による研究

    小林 弘明, 岡澤 厚, 小島 憲道, 川崎 郁斗, 渡邊 功雄

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • アニオン性スピロピランを挿入したコバルト層状水酸化物の開発とその光磁性

    田中 成, 岡澤 厚, 小島 憲道

    日本化学会第94春季年会  

    発表年月: 2014年03月

  • メスバウアー分光とミュオン分光からみた動的および静的スピンクロスオーバー鉄(II)錯体におけるスピンダイナミクス

    岡澤 厚, 小林弘明, 小島憲道, 川崎郁斗, 渡邊功雄

    第16回メスバウアー分光研究会シンポジウム  

    発表年月: 2014年03月

  • メスバウアー分光を用いたシアノ架橋錯体の電極反応の解析

    大久保 將史, 西村 真一, 山田 淳夫, 水野 善文, 朝倉 大輔, 岡澤 厚, 小島 憲道

    第15回メスバウアー分光研究会シンポジウム  

    発表年月: 2014年03月

  • 光異性化分子を対アニオンに導入したスピンクロスオーバー鉄錯体の磁気特性

    菅原 哲, 亀渕 萌, 岡澤 厚, 小島 憲道

    第15回メスバウアー分光研究会シンポジウム  

    発表年月: 2014年03月

  • スピン平衡を示すスピンクロスオーバー鉄(II)錯体におけるメスバウアー分光とミュオン分光からみた動的挙動

    小林 弘明, 岡澤 厚, 小島 憲道, 川崎 郁斗, 渡邊 功雄

    第15回メスバウアー分光研究会シンポジウム  

    発表年月: 2014年03月

  • スピン平衡を示す鉄(II)錯体のメスバウアー分光およびミュオン分光からみた動的挙動

    小林 弘明, 岡澤 厚, 川崎 郁斗, 渡邊 功雄, 小島 憲道

    平成25年度KUR専門研究会「不安定原子核の理工学と物性応用研究III」  

    発表年月: 2013年12月

  • Development of the proton responsive spin-crossover complex film and its electrical control of the spin state accompanied by proton conduction

    H. Kamebuchi, T. Jo, A. Okazawa, N. Kojima

    4th Asian Conference on Coordination Chemistry (ACCC4)  

    発表年月: 2013年11月

  • [Dy2M]型4f-3dヘテロスピン錯体における単分子磁石挙動の化学修飾

    岡澤 厚, 石田 尚行, 野尻 浩之, 小島 憲道

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 鉄混合原子化錯体の特異な電荷移動挙動に対するコバルト置換効果

    豊田 靖央, 井田 博道, 稲葉 道一, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 層間相互作用スイッチとしての光異性化分子を挿入した銅層状水酸化物の磁気挙動制御

    川上 日向子, 久保田 尚子, 田中 美幸, 大島 祐史, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 光異性化配位子を含む金属錯体を挿入したコバルト層状磁性体の開発

    稲田 雄, 久保田 尚子, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • アニオン性スピロピランを挿入したコバルト層状水酸化物の合成とその光磁性

    田中 成, 菅原 哲, 岡澤 厚, 小島 憲道

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 分子分極を持つローター分子を挿入した鉄混合原子価錯体における電荷移動挙動の変化

    新井 一馬, 井田 博道, 岡澤 厚, 榎本 真哉, 小島 憲道

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 層間分子がもたらす鉄混合原子価錯体における磁性層の歪みによる電荷移動挙動の変化

    佐々木 翔太郎, 井田 博道, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • コバルト層状磁性体における光異性化分子のπ電子系スイッチを利用した強磁性転移温度の制御

    久保田 尚子, 大島 祐史, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • ジチオオキサレート架橋Fe二核ユニットにおける分子間相互作用を介したスピンクロスオーバー挙動の変化

    山科 駿, 坂口 岳志, 井田 博道, 小島 憲道, 岡澤 厚, 榎本 真哉

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • かさ高いアリール基を有する有機鉄二価錯体の合成と物性

    合田 舜, 松尾 司, 伊藤 幹直, 橋爪 大輔, 玉尾 皓平, 岡澤 厚, 小島 憲道, 小林 義男

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • スピンクロスオーバー錯体における動的スピン平衡のミューオンスピン分光による研究

    小林 弘明, 岡澤 厚, 小島 憲道, 川崎 郁斗, 渡邊 功雄

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • 光異性化分子を対アニオンとしたスピンクロスオーバー鉄(III)錯体[FeIII(qsal)2]SP (SP = spiropyran)の光照射による磁性変換

    亀渕 萌, 菅原 哲, 岡澤 厚, 小島 憲道

    錯体化学会第63回討論会  

    発表年月: 2013年11月

  • Study on spin configurations in photoresponsive iron mixed-valence complexes by Mossbauer spectroscopy

    A. Okazawa, J. Yoshida, N. Kida, I. Kashima, W. Murata, M. Enomoto, N. Kojima

    International Conference on the Applications of the Mossbauer Effect 2013 (ICAME2013)  

    発表年月: 2013年09月

  • Study on concerted phenomena coupled with rapid spin-equilibrium and magnetic phase transition for (C6H5)4P[MnIIFeIII(C2O3S)3] by 57Fe Mossbauer spectroscopy

    N. Kojima, K. Kagesawa, A. Okazawa, M. Enomoto

    International Conference on the Applications of the Mossbauer Effect 2013 (ICAME2013)  

    発表年月: 2013年09月

  • Magnetostructural correlation for 1D spin-crossover system, [FeII(NH2-triazole)3(CnH2n+1SO3)2-xH2O

    H. Kamebuchi, A. Nakamoto, M. Enomoto, T. Yokoyama, N. Kojima

    International Conference on the Applications of the Mossbauer Effect 2013 (ICAME2013)  

    発表年月: 2013年09月

  • プルシアンブルー類似体におけるマグネシウムイオン挿入・脱離反応の解析

    水野善文, 大久保將史, 朝倉大輔, 影澤幸一, 岡澤 厚, 小島憲道, 大石克嘉, 工藤徹一, 周 豪慎

    第53回電池討論会  

    発表年月: 2012年11月

  • Topotactic Solid State Redox of a Cyano-bridged Magnet

    M. Okubo, K. Kagesawa, Y. Mizuno, D. Asakura, H. S. Zhou, A. Okazawa, N. Kojima

    The 13th International Conference on Molecule-based Magnets (ICMM2012)  

    発表年月: 2012年10月

  • Cation Size Effect on Photomagnetism and Charge Transfer Phase Transition of Iron Mixedvalence Complexes with Spiropyrans

    J. Yoshida, N. Kida, A. Okazawa, N. Kojima

    The 13th International Conference on Molecule-based Magnets (ICMM2012)  

    発表年月: 2012年10月

  • Precise Electrochemical Control of Ferromagnetism in a Bimetallic NiFe Prussian Blue Analog

    Y. Mizuno, M. Okubo, K. Kagesawa, D. Asakura, T. Kudo, H. Zhou, K. Oh-ishi, A. Okazawa, N. Kojima

    The 13th International Conference on Molecule-based Magnets (ICMM2012)  

    発表年月: 2012年10月

  • Electric-Field Manipulation of the Spin State in Transparent pH-Sensitive Spin-Crossover Complex, [FeII(diAMsar)]@Nafion

    H. Kamebuchi, T. Jo, A. Okazawa, M. Enomoto, N. Kojima

    The 13th International Conference on Molecule-based Magnets (ICMM2012)  

    発表年月: 2012年10月

  • Chemical Modification of 4f-3d Heterometallic [Ln2Ni]-type Single-Molecule Magnets

    A. Okazawa, T. Ishida, H. Nojiri, S. Yoshii, N. Kojima

    The 13th International Conference on Molecule-based Magnets (ICMM2012)  

    発表年月: 2012年10月

  • レドックス活性白金錯体の磁性

    吉田 真那, 岡澤 厚, 渡邉 永治, 小島 憲道, 松下 信之

    錯体化学会第62回討論会  

    発表年月: 2012年09月

  • 特異な環状π電子系分子およびその前駆体を挿入した鉄混合原子価錯体における電荷移動挙動の制御

    白川 雅彦, 井田 博道, 榎本 真哉, 岡澤 厚, 小島 憲道, 佐藤 潔

    錯体化学会第62回討論会  

    発表年月: 2012年09月

  • シュウ酸およびジチオシュウ酸に架橋された新奇二核鉄錯体の合成と物性

    井田 博道, 岡澤 厚, 小島 憲道, 榎本 真哉

    錯体化学会第62回討論会  

    発表年月: 2012年09月

  • アニオン性スピロピランを対イオンとするトリアゾール架橋鉄(II)錯体の合成とスピンクロスオーバー挙動

    田中 成, 菅原 哲, 岡澤 厚, 小島 憲道

    錯体化学会第62回討論会  

    発表年月: 2012年09月

  • ピリジンやピリミジンを含む新規ニトロキシドキレート錯体の合成と性質

    本間 雄太, 岡澤 厚, 石田 尚行

    第6回分子科学討論会  

    発表年月: 2012年09月

  • シアノ架橋配位高分子における固体電気化学反応による磁性制御

    大久保 將史, 影澤 幸一, 水野 善文, 朝倉 大輔, 細野 英司, 工藤 徹一, 周 豪慎, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2012年09月

  • モノチオオキサラト架橋鉄混合原子価錯体におけるスピン平衡と原子価揺動

    吉田 順哉, 影澤 幸一, 岡澤 厚, 榎本 真哉, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2012年09月

  • pH応答スピンクロスオーバー錯体膜の開発と電場によるスピン状態の時空間制御

    亀渕 萌, 城 健智, 岡澤 厚, 榎本 真哉, 清水 秀治, 小島 憲道

    第6回分子科学討論会  

    発表年月: 2012年09月

  • 単分子磁石を目指したニトロキシドラジカル-ランタノイド錯体の磁性の解明

    村上 里奈, 岡澤 厚, 吉居 俊輔, Michael L. Baker, 野尻 浩之, 石田 尚行

    第6回分子科学討論会  

    発表年月: 2012年09月

  • Ferro- and Antiferromagnetic Couplings of (MV)Cu2Cl6 (MV = methylviologen)

    Y. Seki, A. Okazawa, M. Enomoto, J. Harada, K. Ogawa, N. Kojima

    XXIst International Symposium on the Jahn-Teller Effect (JT2012)  

    発表年月: 2012年08月

  • ランタノイド−ニトロキシドラジカル錯体系の単分子磁石の探索

    村上 里奈, 岡澤 厚, 吉居 俊輔, 野尻 浩之, 石田 尚行

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 4f-3d錯体における交換相互作用と磁気異方性

    島田 貴士, 岡澤 厚, 吉居 俊輔, 野尻 浩之, 石田 尚行

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 電荷移動錯体β’’-[BEDT-TTF]4[ReCl4(oxalate)](C6H5CN)の結晶構造と伝導性

    霜鳥 文俊, 榎本 真哉, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 基底三重項ピリミジン-4,6-ジイルビス(tert-ブチルニトロキシド)の合成と性質

    本間 雄太, 岡澤 厚, 石田 尚行

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 直線二配位Fe錯体の巨大内部磁場(2)

    小林 義男, 伊藤 幹直, 松尾 司, 森 雅樹, 中村 仁, 岡澤 厚, 小島 憲道, 玉尾 皓平

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 鉄混合原子価錯体[FeIIFeIII(C2O2S2)3]におけるマンガンによる磁性イオン置換効果

    井田 博道, 榎本 真哉, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • アニオン性スピロピランを対イオンに用いたスピンクロスオーバー鉄錯体の磁性

    菅原 哲, 田中 成, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • モノチオオキサレート架橋鉄錯体における動的スピンクロスオーバー現象の圧力効果

    松岡 貴文, 影澤 幸一, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 光応答性鉄混合原子価錯体(SP-R)[FeIIFeIII(dto)3](SP = spiropyran; R = alkyl group; dto = C2O2S2)における磁気特性の対カチオンサイズ効果の研究

    吉田 順哉, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 2種類のジアリールエテン誘導体を挿入したコバルト層状水酸化物における光誘起多段階磁気制御

    大島 裕史, 榎本 真哉, 岡澤 厚, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • ベルダジルラジカルが配位した新奇鉄(II)錯体[FeII(vdco)2(H2O)2]2H2Oの結晶構造と物性:水分子の配向挙動に起因する57Feメスバウアースペクトルの異常な振舞いの解明

    亀渕 萌, 岡澤 厚, 榎本 真哉, 原田 潤, 小川 桂一郎, 大久保 将史, Train, Cyrille・Verdaguer, Michel, 丸田 悟朗, 武田 定, 小島 憲道

    日本化学会第92春季年会  

    発表年月: 2012年03月

  • 57Feメスバウアー分光法を用いた集積型混合原子価鉄錯体の強磁性相および原子価揺動の研究

    岡澤厚, 小島憲道

    メスバウアー分光研究会  

    発表年月: 2012年03月

  • 直線型二配位鉄錯体のメスバウアー分光研究(III)

    小林義男, 松尾 司, 伊藤幹直, 長友 傑, 中村 仁, 森 雅樹, 岡澤 厚, 小島憲道, 玉尾皓平

    京都大学原子炉実験所専門研究会「不安定原子核の理工学と物性応用研究」  

    発表年月: 2011年12月

  • t-ブチル2-ピリジルニトロキシド-ランタノイド(Ln = Gd, Tb, Dy)錯体における比較的強い反強磁性的相互作用

    村上里奈, 岡澤厚, 吉居俊輔, 野尻浩之, 石田尚行

    第50回電子スピンサイエンス学会年会  

    発表年月: 2011年11月

  • ピリミジン-4,6-ジイルビス(tert-ブチルニトロキシド)の合成及び性質

    本間雄太, 岡澤厚, 石田尚行

    第50回電子スピンサイエンス学会年会  

    発表年月: 2011年11月

  • Study on the Ferromagnetic State in Iron Mixed-Valence Complexes A[FeIIFeIII(dto)3] (A = (n-CnH2n+1)4N, Spiropyrna; dto = C2O2S2) by Means of Mossbauer Spectroscopy

    Y. Ono, A. Okazawa, N. Kida, J. Yoshida, M. Enomoto, N. Kojima

    31th International Conference on the Applications of the M?ssbauer Effect (ICAME2011)  

    発表年月: 2011年09月

  • 5配位ゲルマニウム配位子を有する鉄ジカルボニル錯体の合成と構造

    狩野 直和, 吉成 直人, 川島 隆幸, 榎本 真哉, 岡澤 厚, 小島 憲道

    第60回錯体化学討論会  

    発表年月: 2011年09月

  • アルカリ金属イオンによるプルシアンブルー類似体における磁気特性の制御

    水野 善文, 大久保 將史, 朝倉 大輔, 大石 克嘉, 工藤 徹一, 周 豪慎, 岡澤 厚, 小島 憲道

    第5回分子科学討論会  

    発表年月: 2011年09月

  • ラジカル二座配位子を目指したピリミジン-4,6-ジイルビス(tert-ブチルニトロキシド)の合成

    本間 雄太, 岡澤 厚, 石田 尚行

    第22回基礎有機化学討論会  

    発表年月: 2011年09月

  • 無欠陥型プルシアンブルー類似体のリチウムイオン二次電池用電極特性へのFe置換効果

    水野 善文, 大久保 將史, 朝倉 大輔, 大石 克嘉, 工藤 徹一, 周 豪慎, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • プルシアンブルー類似体におけるイオンによる可逆的磁性スイッチング

    大久保 將史, 水野 善文, 朝倉 大輔, 工藤 徹一, 周 豪慎, 池戸 一道, 溝川 貴司, 本間 格, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • 直線三核 Cu-Ln-Cu 金属錯体における交換相互作用のランタノイドイオン依存性

    島田 貴士, 藤原 慶, 岡澤 厚, 田中 豪, 吉居 俊輔, 野尻 浩之, 石田 尚行

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • 4f-3d系錯体におけるランタノイド-ニッケルイオン間に働く交換相互作用の決定

    岡澤 厚, 石田 尚行, 吉居 俊輔, 野尻 浩之, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • アルカリ金属イオンによるプルシアンブルー類似体における磁気制御

    水野 善文, 大久保 將史, 朝倉 大輔, 大石 克嘉, 工藤 徹一, 周 豪慎, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • モノチオオキサレート架橋集積型ヘテロ金属錯体におけるスピン平衡と磁気特性

    影澤 幸一, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • モノチオオキサレート架橋鉄錯体におけるスピンクロスオーバー現象のカチオンサイズ効果

    松岡 貴文, 影澤 幸一, 岡澤 厚, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • 光異性化分子を対イオンに用いたスピンクロスオーバー鉄(III)錯体の構造と磁性

    菅原 哲, 岡澤 厚, 原田 潤, 小川 桂一郎, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • pH依存スピンクロスオーバー錯体膜における動的スピン転移挙動

    亀渕 萌, 城 健智, 清水 秀治, 岡澤 厚, 榎本 真哉, 小島 憲道

    錯体化学会第61回討論会  

    発表年月: 2011年09月

  • Synthesis and Structures of Anionic Iron Complexes bearing a Pentacoordinated Silicon or Germanium Atom

    N. Kano, N. Yoshinari, T. Kawashima, M. Enomoto, A. Okazawa, N. Kojima, J.-D. Guo, S. Nagase

    16th International Symposium on Silicon Chemistry (ISOS XVI)  

    発表年月: 2011年08月

  • 4f-3d金属三核錯体における交換相互作用のランタノイドイオン依存性

    島田 貴士, 藤原 慶, 岡澤 厚, 田中 豪, 吉居 俊輔, 野尻 浩之, 石田 尚行

    日本化学会第91春季年会  

    発表年月: 2011年03月

  • (n-CnH2n+1)4N[ZnIIFeIII(C2O3S)3](n = 2-4)におけるカチオンサイズ効果を用いたスピン平衡の制御

    影澤 幸一, 岡澤 厚, 小島 憲道

    日本化学会第91春季年会  

    発表年月: 2011年03月

  • 光異性化分子ジアリールエテンをインターカレートした有機無機ハイブリッドシステムの構築

    小林 克彦, 岡澤 厚, 小島 憲道

    日本化学会第91春季年会  

    発表年月: 2011年03月

  • ジアセチレンをインターカレートした磁性有機・無機ハイブリッドシステムの構築

    石田 拓也, 岡澤 厚, 小島 憲道

    日本化学会第91春季年会  

    発表年月: 2011年03月

  • スピン転移類似挙動を示すπ-d へテロスピン系」、新学術領域研究「分子自由度が拓く新物質科学

    石田尚行, 岡澤 厚

    新学術領域研究「分子自由度が拓く新物質科学」第4回領域会議  

    発表年月: 2011年01月

  • Study on the spin equilibrium and magnetic ordering in Ph4P[MnIIFeIII(mto)3] (Ph = C6H5, mto = C2O3S)

    K. Kagesawa, A. Okazawa, M. Enomoto, N. Kojima

    2010 International Chemical Congress of Pacific Basin Societies (Pacifichem 2010)  

    発表年月: 2010年12月

  • Spin-transition-like behavior of radical chelate complexes accompanied by twisted deformation around a copper(II)-nitroxide coordination bond

    A. Okazawa, T. Ishida, N. Kojima

    2010 International Chemical Congress of Pacific Basin Societies (Pacifichem 2010)  

    発表年月: 2010年12月

  • Study on the magnetism and anomalous behavior of 57Fe Mossbauer spectra for iron(II) complex coordinated by verdazyl radical

    H. Kamebuchi, A. Okazawa, M. Enomoto, J. Harada, K. Ogawa, M. Okubo, C. Train, M. Verdaguer, N. Kojima

    2010 International Chemical Congress of Pacific Basin Societies (Pacifichem 2010)  

    発表年月: 2010年12月

  • Determination of exchange couplings in dinuclear 4f-3d heterometallic nanosized magnets

    T. Ishida, R. Watanabe, K. Fujiwara, A. Okazawa, G. Tanaka, S. Yoshii, H. Nojiri

    2010 International Chemical Congress of Pacific Basin Societies (Pacifichem 2010)  

    発表年月: 2010年12月

  • Control of Magnetic Properties and Electronic Structures in Prussian Blue Analogues by Electrochemical Ion Extraction

    M. Okubo, D. Asakura, T. Kudo, H. Zhou, K. Ikedo, T. mizokawa, A. Okazawa, N. Kojima

    60th Annversary Conference on Coordination Chemistry in OSAKA, Japan (60CCCO)  

    発表年月: 2010年09月

  • 光応答性有機分子をインターカレートした層状ペロブスカイト型銅錯体の構築と物性

    関 泰史, 岡澤 厚, 原田 潤, 小川 桂一郎, 小島 憲道

    第60回錯体化学討論会  

    発表年月: 2010年09月

  • かご型配位子を有する新規スピンクロスオーバー錯体膜の開発とそのpH依存性

    亀渕 萌, 城 健智, 岡澤 厚, 榎本 真哉, 小島 憲道

    第60回錯体化学討論会  

    発表年月: 2010年09月

  • 集積型金属錯体[M(II)Fe(III)(mto)3] (mto = C2O3S)における速いスピン平衡と磁気特性

    影澤 幸一, 岡澤 厚, 小島 憲道

    第60回錯体化学討論会  

    発表年月: 2010年09月

  • Kイオン脱離過程におけるプルシアンブルー類似体の磁気状態変化

    朝倉大輔, 大久保將史, 工藤徹一, 周豪慎, 溝川貴司, 岡澤厚, 小島憲道

    日本物理学会2010年秋季大会  

    発表年月: 2010年09月

  • ランタノイドイオンと銅イオンを組み合せた単分子磁石における交換相互作用の解明

    藤原 慶, 渡邉 亮, 岡澤 厚, 田中 豪, 吉居 俊輔, 野尻 浩之, 石田 尚行

    第4回分子科学討論会  

    発表年月: 2010年09月

  • プルシアンブルー類似体のKイオン脱離過程における電子状態・磁性変化

    大久保 將史, 朝倉 大輔, 工藤 徹一, 周 豪慎, 池戸 一道, 溝川 貴司, 岡澤 厚, 小島 憲道

    第4回分子科学討論会  

    発表年月: 2010年09月

  • 速いスピン平衡を有する集積型金属錯体[MnII FeIII(mto)3](mto = C2O3S)における特異な磁気相転移

    影澤 幸一, 岡澤 厚, 小島 憲道

    第4回分子科学討論会  

    発表年月: 2010年09月

  • 光酸化還元機能を有するビオロゲンを対カチオンとする一次元白金錯体の合成・構造・物性

    関 泰史, 岡澤 厚, 榎本 真哉, 原田 潤, 小川 桂一郎, 小島 憲道

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • プロトン濃度による磁性制御を目ざしたスピンクロスオーバー錯体膜の開発

    城 健智, 榎本 真哉, 岡澤 厚, 小島 憲道

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • ベルダジルラジカル―鉄(II)錯体の結晶水が配位子場に与える影響

    亀渕 萌, 岡澤 厚, 榎本 真哉, 原田 潤, 小川 桂一郎, 大久保 将史, Train, Cyrille・Verdaguer, Michel, 田所 誠, 小島 憲道

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • [Fe(4-NH2trz)3](X)2(X = tos, abs)におけるカウンターアニオンの構造異性がスピンクロスオーバー挙動に及ぼす効果

    菅原 哲, 岡澤 厚, 榎本 真哉, 小島 憲道

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • (C6H5)4P[MnIIFeIII(C2O3S)3]における速いスピン平衡と磁気秩序化に関する研究

    影澤 幸一, 岡澤 厚, 榎本 真哉, 小島 憲道

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • サレン型配位子を用いてランタノドイオンと遷移金属イオンを組み合わせたヘテロスピン2核錯体の交換相互作用

    渡邉 亮, 藤原 慶, 岡澤 厚, 田中 豪, 吉居 俊輔, 野尻 浩之, 石田 尚行

    日本化学会第90春季年会  

    発表年月: 2010年03月

  • 鉄混合原子価錯体(CnH2n+1)4N[Fe(II)Fe(III)(mto)3](n = 3,4; mto = C2O3S)における速いスピン平衡と電荷揺動の協奏現象

    影澤幸一, 岡澤厚, 榎本真哉, 小島憲道

    京都大学原子炉実験所専門研究会「短寿命核および放射線を用いた物性研究(II)」  

    発表年月: 2009年12月

  • ランタニドイオンと遷移金属イオンを組み合せた新規な単分子磁石開発とその磁気構造の解明

    藤原 慶, 渡邉 亮, 岡澤 厚, 野尻浩之, 石田尚行

    東京農工大学・電気通信大学第六回合同シンポジウム「ナノ未来材料とコヒーレント光科学」  

    発表年月: 2009年12月

  • Ln(III)-V(IV)錯体の磁気構造の解明とLn(III)-Cu(II)錯体との比較

    渡邉 亮, 岡澤 厚, 藤原 慶, 野上 隆, 野尻浩之, 石田尚行

    第48回電子スピンサイエンス学会年会  

    発表年月: 2009年11月

  • RE-3dヘテロメタル分子磁石のESRによる評価

    野尻浩之, 林美咲, 田中豪, 吉居俊輔, A. Gomella, 石田尚行, 岡澤厚

    第48回電子スピンサイエンス学会年会  

    発表年月: 2009年11月

  • RE-3dヘテロ金属分子磁性体の交換相互作用と磁性

    野尻浩之, 林美咲, 田中豪, 吉居俊輔, 石田尚行, 岡澤厚

    日本物理学会2009年秋季大会  

    発表年月: 2009年09月

  • 遷移金属イオンを変えた[DyMDy]型三核錯体における単分子磁石性能の比較

    岡澤 厚, 野尻 浩之, 野上 隆, 石田 尚行

    第59回錯体化学討論会  

    発表年月: 2009年09月

  • [LnMLn]型錯体における4f-3dスピン間の交換相互作用

    岡澤 厚, 根津 将, 野尻 浩之, 石田 尚行

    第3回分子科学討論会  

    発表年月: 2009年09月

  • 4f-3dヘテロスピン系錯体におけるランタノイドイオン種と交換相互作用との相関

    岡澤 厚, 渡邉 亮, 野尻 浩之, 野上 隆, 石田 尚行

    日本化学会第89春季年会  

    発表年月: 2009年03月

  • サレン型コンパートメント配位子を利用したランタノイド(III)とバナジウム(IV)を組み合わせた錯体の研究

    渡邉 亮, 岡澤 厚, 野尻 浩之, 野上 隆, 石田 尚行

    日本化学会第89春季年会  

    発表年月: 2009年03月

  • 希土類イオンと遷移金属イオンを用いた単分子磁石を目指して

    渡邉 亮, 岡澤 厚, 野尻浩之, 野上 隆, 石田尚行

    東京農工大学・電気通信大学 21 世紀 COE プログラム、第五回合同シンポジウム「ナノ未来材料とコヒーレント光科学」  

    発表年月: 2008年12月

  • ビス(ヘテロアリール)ニトロキシドおよびそのキレート錯体の合成と磁性

    岡澤 厚, 永市泰規, 野上 隆, 石田尚行

    第19回基礎有機化学討論会(第38回構造有機化学討論会)  

    発表年月: 2008年10月

  • Magnetic properties and exchange couplings of one-dimentionally arrayed 4f-3d heterometallic [Ln2Cu2]n compounds

    A. Okazawa, R. Watanabe, H. Nojiri, T. Nogami, T. Ishida

    The 11th International Conference on Molecule-Based Magnets (ICMM2008)  

    発表年月: 2008年09月

  • Strong ferromagnetic exchange couplings in copper(II) and nickel(II) complexes chelated with tert-butyl 5-methoxyphenyl-2-pyridyl nitroxide. A magneto-structural relationship

    A. Okazawa, Y. Terakado, T. Nogami, T. Ishida

    The 11th International Conference on Molecule-Based Magnets (ICMM2008)  

    発表年月: 2008年09月

  • RE-3dヘテロ金属分子磁性体の交換相互作用と磁性

    野尻浩之, 吉居俊輔, 石田尚行, 岡澤厚

    日本物理学会2008年秋季大会  

    発表年月: 2008年09月

  • High-Field ESR on Molecular-Based Nano-Magnets --- Application to Polyhedron Clusters and RareEarth Compounds

    Y. Oshima, H. Nojiri, S. Yoshii, P. K?gerler, M. Luban, A. M?ller, J. Schnack, A. Okazawa, T. Ishida

    Asian-Pacific EPR/ESR Symposium (APES08)  

    発表年月: 2008年07月

  • 複素芳香族の2位に置換したラジカルを用いたキレート錯体の研究

    寺門 雄太郎, 岡澤 厚, 石田 尚行, 野上 隆

    日本化学会第88春季年会  

    発表年月: 2008年03月

  • 単結晶構造相転移に伴うラジカル−銅(II)イオン間強磁性的/反強磁性的相互作用の熱的スイッチ

    岡澤 厚, 橋爪 大輔, 野上 隆, 石田 尚行

    日本化学会第88春季年会  

    発表年月: 2008年03月

  • 直線三核型4f-3dヘテロ金属錯体単分子磁石における交換相互作用の決定

    石田 尚行, 岡澤 厚, 渡邊 亮, 野上 隆, 野尻 浩之

    日本化学会第88春季年会  

    発表年月: 2008年03月

  • Magnetic Properties and Exchange Couplings of One-Dimensionally Arrayed 4f−3d Heterometallic [Ln2Cu2]n Compounds

    The 11th International Conference on Molecule-based Magnets (ICMM2008)  

    発表年月: 2008年

  • Preparation, Structure, and Magnetic Properties of Chelating Compounds of 2-Pyridyl Nitroxide Derivatives

    A. Okazawa, K. Osanai, T. Shimada, T. Nogami, T. Ishida

    The 10th International Conference on Molecule-based Magnets (ICMM 2006)  

    発表年月: 2006年

  • Structures and Magnetic Properties of Dinuclear Spiro-complexes for Orthogonality of Magnetic Orbitals

    A. Okazawa, T. Ishida, T. Nogami

    The 9th International Conference on Molecule-based Magnets (ICMM 2004)  

    発表年月: 2004年

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担当経験のある科目(授業)

  • 基礎科学実験IA, IB, II, III

    東京大学  

  • 物質科学実験I, II

    東京大学  

  • 基礎化学実験

    東京大学