Researcher Database

Masako Kato
Faculty of Science Chemistry Inorganic and Analytical Chemistry
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science Chemistry Inorganic and Analytical Chemistry

Job Title

  • Professor

Degree

  • Doctor of Science(Nagoya University)

URL

J-Global ID

Research Interests

  • Structural Chemistry   Photochemistry   Coordination Chemistry   

Research Areas

  • Nanotechnology/Materials / Inorganic and coordination chemistry

Academic & Professional Experience

  • 2006/04 - Today Hokkaido University Department of Chemistry, Faculty of Science Professor
  • 2013/04 - 2013/09 Ehime University
  • 2012/10 - 2013/03 Nara Women's University
  • 2011/01 - 2011/03 University of Tsukuba
  • 2010/12 - 2010/12 Osaka City University
  • 2010/04 - 2010/09 Okayama University
  • 2010/04 - 2010/09 Kindai University
  • 2009/04 - 2009/09 Gifu University
  • 2002/04 - 2009/03 Nara Women's University Graduate School of Humanities and Sciences
  • 2007/10 - 2008/03 Tokyo Institute of Technology
  • 1996 - 2006 Nara Women's University
  • 1996 - 2006 Associate Professor,Nara Women's University
  • 1998/10 - 2001/09 科学技術振興事業団さきがけ研究21「状態と変革」領域研究員兼任
  • 1996/04 - 1996/08 米国カリフォルニア工科大学客員研究員(文部省在外研究員)
  • 1989 - 1996 Nara Women's University
  • 1989 - 1996 Research Associate,Nara Women's University
  • 1985 - 1989 京都大学 職員(技術系)
  • 1985 - 1989 Technical Staff,Kyoto University
  • 1981 - 1985 岡崎共同利用研究機構分子科学研究所 職員(技術系)
  • 1981 - 1985 Technical Staff,Institute for Molecular Scinece

Education

  • 1979/04 - 1981/03  名古屋大学大学院
  •        - 1981  Nagoya University  Graduate School, Division of Natural Science  Chemistry
  • 1975/04 - 1979/03  Nagoya University  School of Science  Department of Chemistry
  •        - 1979  Nagoya University  Faculty of Science  Chemistry

Association Memberships

  • 日本分析化学会   米国化学会   錯体化学会   光化学協会   日本化学会   The Japan Society for Analytical Chemistry   American Chemical Society   Japan Society of Coordination Chemistry   Japanese Photochemistry Association   Chemical Society of Japan   

Research Activities

Published Papers

  • Fumiya Kobayashi, Ryo Ohtani, Saki Teraoka, Masaki Yoshida, Masako Kato, Yingjie Zhang, Leonard F. Lindoy, Shinya Hayami, Masaaki Nakamura
    Chemistry – A European Journal 25 (23) 5875 - 5879 0947-6539 2019/04/23 [Refereed][Not invited]
  • Hajime Ito, Masako Kato, Hajime Ito, Miki Hasegawa, Kazuyuki Ishii
    Chemistry – A European Journal 25 (20) 5105 - 5112 2019/04/05 [Refereed][Not invited]
  • Masako Kato, Hajime Ito, Miki Hasegawa, Kazuyuki Ishii
    Chemistry – A European Journal Wiley 25 (20) 2019/04 [Refereed][Not invited]
  • Atsushi Kobayashi, Momoko Fujii, Yasuhiro Shigeta, Masaki Yoshida, Masako Kato
    Inorganic Chemistry American Chemical Society ({ACS}) 58 (7) 4456 - 4464 2019/04 [Refereed][Not invited]
  • Atsushi Kobayashi, Kenki Shimizu, Ayako Watanabe, Yuki Nagao, Nobutaka Yoshimura, Masaki Yoshida, Masako Kato
    Inorganic Chemistry American Chemical Society ({ACS}) 58 (4) 2413 - 2421 2019/02 [Refereed][Not invited]
  • Yasuhiro Shigeta, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    European Journal of Inorganic Chemistry Wiley 2019 (7) 1011 - 1017 2019/02 [Refereed][Not invited]
  • Ishigaki Y, Sugawara K, Yoshida M, Kato M, Suzuki T
    Bulletin of the Chemical Society of Japan 92 (7) 1211 - 1217 2019 [Refereed][Not invited]
  • Yamanoi Y, Usuki T, Omoto K, Shimada M, Koike H, Iwamura M, Nozaki K, Saito D, Kato M, Nishihara H
    Tetrahedron Letters 60 (16) 1108 - 1112 2019 [Refereed][Not invited]
  • Yanagida S, Yoshida M, Sameera W.M.C, Kobayashi A, Kato M
    Bulletin of the Chemical Society of Japan 92 (10) 1684 - 1693 2019 [Refereed][Not invited]
  • Otsuka H, Kobayashi A, Yoshida M, Kato M
    Journal of Photochemistry and Photobiology A: Chemistry 369 189 - 194 2019 [Refereed][Not invited]
  • Sun Y, Amsler M, Goedecker S, Caravella A, Yoshida M, Kato M
    CrystEngComm 21 (26) 3949 - 3953 2019 [Refereed][Not invited]
  • Yoshida M, Shitama H, Sameera W.M.C, Kobayashi A, Kato M
    Chemistry - A European Journal 25 (32) 7669 - 7678 2019 [Refereed][Not invited]
  • Shigeta Y, Kobayashi A, Yoshida M, Kato M
    Inorganic Chemistry 58 (11) 7385 - 7392 2019 [Refereed][Not invited]
  • Dosen M, Kawada Y, Shibata S, Tsuge K, Sasaki Y, Kobayashi A, Kato M, Ishizaka S, Kitamura N
    Inorganic Chemistry 58 (13) 8419 - 8431 2019 [Refereed][Not invited]
  • Tomohiro Ogawa, W. M. C. Sameera, Daisuke Saito, Masaki Yoshida, Atsushi Kobayashi, Masako Kato
    Inorganic Chemistry American Chemical Society ({ACS}) 2018/11 [Refereed][Not invited]
  • Yasuhiro Shigeta, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    Crystal Growth and Design 18 (6) 3419 - 3427 1528-7505 2018/06/06 [Refereed][Not invited]
     
    A novel Pt(II) diimine complex, [Pt(CN)2(H2dpcpbpy)] (1, H2dpcpbpy = 4,4′-di(p-carboxyphenyl)-2,2′-bipyridine), was synthesized, and its vapochromic behavior was investigated. The yellow amorphous form of 1, 1-Ya, transformed into the porous orange crystalline form, 1-Oc, upon exposure to ethanol vapor. This behavior is similar to that of the previously reported complex, [Pt(CN)2(H2dcphen)] (2, H2dcphen = 4,7-dicarboxy-1,10-phenanthroline). X-ray diffraction study showed that 1-Oc possessed similar but larger porous channels (14.3 × 8.6 Å) compared to the red crystalline form of 2, 2-Rc (6.4 × 6.8 Å). Although the porous structure of 2-Rc was retained after vapor desorption, that of 1-Oc collapsed to form the orange amorphous solid, 1-Oa. However, the orange color was unchanged in this process. The initial color was recovered by grinding 1-Oa and 2-Rc. These vapor-writing and grinding-erasing functions can be applied to both in situ vapor sensing and vapor-history sensing, i.e., sensors that can memorize the existence of previous vapors. A notable difference was observed for humid air sensitivity the orange emission of 1-Oa was largely unaffected upon exposure to humid air, whereas the red emission of 2-Rc was significantly affected. The lesser sensitivity of 1-Oa toward humidity is important for stable vapor-history sensor applications.
  • Atsushi Kobayashi, Shuhei Watanabe, Masaki Yoshida, Masako Kato
    ACS Applied Energy Materials American Chemical Society ({ACS}) 1 (6) 2882 - 2890 2018/06 [Refereed][Not invited]
  • Panyi Liang, Atsushi Kobayashi, W. M.C. Sameera, Masaki Yoshida, Masako Kato
    Inorganic Chemistry 57 (10) 5929 - 5938 1520-510X 2018/05/21 [Refereed][Not invited]
     
    Luminescent [Cu2I2(pyrpy)2(PR3)2] complexes (pyrpy = 4-pyrrolidinopyridine PR3 = triphenylphosphine (1), tri-m-tolylphosphine (2), tri-p-tolylphosphine (3)) were prepared by solution reactions and a rarely reported solvent-free thermal method. X-ray structure analyses reveal that complexes composed of dinuclear {Cu2I2} cores surrounded by two PR3 and two pyrpy ligands were formed. Although the melting point of pyrpy is the lowest among the organic units used in this study, the temperature required to form the luminescent dinuclear complex, prepared by the thermal synthesis method, depended strongly on the PR3 moiety. Two of the three complexes (1 and 3) were successfully prepared by the solvent-free thermal method. Complexes 1-3 exhibited blue emissions at around 450 nm with moderately high quantum yields (φ) of 0.24, 0.31, and 0.51, respectively. Emission-lifetime measurements and time-dependent density functional theory (TD-DFT) calculations suggest thermally activated delayed fluorescence (TADF) in each complex. This solvent-free thermal synthesis of TADF materials represents a promising method for the preparation of luminescent layers directly onto substrates of thin-layer electronic devices, such as organic light-emitting diodes.
  • Masaki Yoshida, Kento Saito, Hiroki Matsukawa, Sae Yanagida, Masanori Ebina, Yoshifumi Maegawa, Shinji Inagaki, Atsushi Kobayashi, Masako Kato
    Journal of Photochemistry and Photobiology A: Chemistry 358 334 - 344 1010-6030 2018/05/01 [Refereed][Not invited]
     
    Pt(II) complexes have been immobilized on a periodic mesoporous organosilica (PMO) consisting of 2,2′-bipyridine (bpy) units bridged by siloxane bonds (BPy-PMO). Although these Pt(II) complexes are luminescent in their discrete molecular states, the luminescence properties of the immobilized complexes largely depend on the origin of the emission luminescence is quenched when the emission originates from the 3ππ* excited state of bipyridine due to the coupling of the C–H bending vibration of the bpy and the Si-O stretching vibration of the siloxane framework, while luminescence is maintained when the 3ππ* excited state of bipyridine is not the lowest excited state. Although the simple coexistence of Pt(0) nanoparticles and Pt(II) complexes did not catalyze water reduction even in the presence of an electron relay, photocatalytic water reduction is observed when Pt(0)/Pt(II)-co-immobilized BPy-PMOs are used. This result clearly demonstrates the importance of the integration of photosensitizers and catalysts on the PMO for enhancing intermolecular electron-transfer processes.
  • Masaki Yoshida, Masako Kato
    Coordination Chemistry Reviews 355 101 - 115 0010-8545 2018/01/15 [Refereed][Not invited]
     
    Double-decker platinum complexes with N-heteroaromatic ligands have attracted increasing interest due to their outstanding luminescent properties and rich redox behavior. In this review, the design principles and recent observations on luminescent and redox-active double-decker platinum complexes are discussed. Because these properties are precisely controlled by intra- and intermolecular Pt⋯Pt electronic interactions, double-decker platinum complexes have been also used to obtain phenomena driven by stimulus–responsive color and luminescence change, such as vapochromism, mechanochromism, thermochromism, and electrochromism. This review also summarizes chromic materials based on double-decker platinum complexes influenced by changes in the Pt⋯Pt electronic interactions.
  • Kitano H, Kobayashi A, Yoshida M, Kato M
    Sustainable Energy and Fuels 2 (12) 2609 - 2615 2018 [Refereed][Not invited]
  • Tomohiro Ogawa, W. M. C. Sameera, Masaki Yoshida, Atsushi Kobayashi, Masako Kato
    Dalton Transactions Royal Society of Chemistry ({RSC}) 47 (16) 5589  2018 [Refereed][Not invited]
  • A. Kobayashi, Y. Yoshida, M. Yoshida, M. Kato
    Chem. Eur. J. 24 (55) 14750 - 14759 2018 [Refereed][Not invited]
  • Hirotsugu Kitano, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    Sustainable Energy & Fuels Royal Society of Chemistry ({RSC}) 2018 [Refereed][Not invited]
  • Tomohiro Ogawa, W. M.C. Sameera, Masaki Yoshida, Atsushi Kobayashi, Masako Kato
    Dalton Transactions 47 (16) 5589 - 5594 1477-9234 2018 [Refereed][Not invited]
     
    Luminescent ionic liquids, based on anionic Pt(ii) complexes, were developed. Depending on the cyclometalating ligands used, they exhibit thermochromic luminescence with different colours. The chromic properties in the flexible liquid and glass states emerge through the self-assembling character of the square-planar Pt(ii) complexes.
  • Atsushi Kobayashi, Naotaka Yamamoto, Yasuhiro Shigeta, Masaki Yoshida, Masako Kato
    Dalton Transactions 47 (5) 1548 - 1556 1477-9234 2018 [Refereed][Not invited]
     
    A luminescent Pt(ii) complex [Pt(CN)2(H4dpbpy)] (1P H4dpbpy = 2,2′-bipyridine-4,4′-diphosphonic acid) bearing a phosphonic-acid-functionalized bipyridine ligand was successfully synthesized and its unique two-way vapochromic behaviour investigated. X-ray structure analyses of both the anhydrous 1P and penta-hydrated 1P·5H2O phases clearly reveal the activation of intermolecular Pt⋯Pt interactions through the adsorption of water vapour. Emission spectroscopy reveals that the penta-hydrated 1P·5H2O complex exhibits an orange emission at 585 nm that shifts in two directions, to a blue-green emission at 469 nm by drying at 100 °C or to a red emission at 701 nm by drying under vacuum at room temperature. Thermogravimetric analyses and powder X-ray diffraction studies clearly reveal that anhydrous 1P, with negligible intermolecular Pt⋯Pt interactions, is formed by drying at 100 °C whereas the monohydrate 1P·H2O phase, with effective Pt⋯Pt interactions, is formed by drying under vacuum.
  • Panyi Liang, Atsushi Kobayashi, Tatsuya Hasegawa, Masaki Yoshida, Masako Kato
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2017 (44) 5134 - 5142 1434-1948 2017/12 [Refereed][Not invited]
     
    Mononuclear Cu-I iodide complexes, [CuI(PPh3)(2)L] {PPh3 = triphenylphosphine; L = 4-aminoisoquinoline (4-aiq) (2), 5-aminoisoquinoline (5-aiq) (3), and 5-nitroisoquinoline (niq) (4)}, were prepared by three different methods: normally used reactions in the solution state, mechanochemical synthesis, and newly developed solvent-free thermal synthesis. Although no solvent was required for the mechanochemical synthesis of the parent complex [CuI(PPh3)(2)(iq)] (1; iq = isoquinoline), a minimal amount of assisting solvent (PhCN) was required for the mechanochemical syntheses of the three functionalized isoquinoline complexes. The amino-functionalized isoquinoline complexes were successfully synthesized by heating the ground mixture of three types of starting materials at ca. 100 degrees C, where the PPh3 ligand melted to promote complex formation by acting as the ligand and the solvent. The emission properties strongly depend on the L ligand: Complexes 2 and 3 showed vibronic emission spectra originating from the (3)* excited state localized on the L ligand, whereas complex 4 did not show any emission in the visible region.
  • Akhilesh K. Sharma, W. M. C. Sameera, Masayoshi Jin, Laksmikanta Adak, Chiemi Okuzono, Takahiro Iwamoto, Masako Kato, Masaharu Nakamura, Keiji Morokuma
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 139 (45) 16117 - 16125 0002-7863 2017/11 [Refereed][Not invited]
     
    The mechanism of the full catalytic cycle for Fe-chiral-bisphosphine-catalyzed cross-coupling reaction between alkyl halides and Grignard reagents (Nakamura and co-workers, J. Am. Chem. Soc. 2015, 137, 7128) was rationalized by using density functional theory (DFT) and multicomponent artificial force-induced reaction (MC-AFIR) methods. The computed mechanism consists of (a) C-Cl activation, (b) transmetalation, (c) C-Fe bond formation, and (d) C-C bond formation through reductive elimination. Our survey on the prereactant complexes suggested that formation of Fe-II(BenzP*)Ph-2 and Fe-I(BenzP*)Ph complexes are thermodynamically feasible. Fe-I(BenzP*)Cl complex is the active intermediate for C-Cl activation. Fe-II(BenzP*)Ph-2 complex can be formed if the concentration of Grignard reagent is high. However, it leads to biphenyl (byproduct) instead of the cross-coupling product. This explains why slow addition of Grignard reagent is critical for the cross-coupling reaction. The MC-AFIR method was used for systematic determination of transition states for C-Fe bond formation and C-C bond formation starting from the key intermediate Fe-II(BenzP*)PhCl. According to our detailed analysis, C-C bond formation is the selectivity-determining step. The computed enantiomeric ratio of 95:5 is in good agreement with the experimental ratio (90:10). Energy decomposition analysis suggested that the origin of the enantioselectivity is the deformation of Ph-ligand in Fe-complex, which is induced by the bulky tert-butyl group of BenzP* ligand. Our study provides important mechanistic insights for the cross-coupling reaction between alkyl halides and Grignard reagents and guides the design of efficient Fe-based catalysts for cross-coupling reactions.
  • Atsushi Kobayashi, Shuhei Watanabe, Masanori Ebina, Masaki Yoshida, Masako Kato
    JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 347 9 - 16 1010-6030 2017/10 [Refereed][Not invited]
     
    Two heteroleptic Ir(III) complexes bearing two diethyl phosphonate groups, [Ir(ppy-PE)(2)(bpy)(PF6) and [Ir(ppy)(2)(bpy-dPE)](PF6) (1pPE and 1bPE; Hppy = 2-phenylpyridine, Hppy-PE =4-(diethylphosphonomethyl)-2-phenylpyridine, bpy = 2,2'-bipyridine, bpy-dPE=4,4'-bis(diethylphosphonomethyl)-2,2'bipyridine), were successfully synthesized, and their photophysical properties were investigated by UV-vis absorption and emission spectroscopic and electrochemical measurements. Both IpPE and IbPE complexes exhibited similar IJV-vis absorption and emission spectra and cyclic voltammograms as those of nonmodified complex [Ir(ppy)2(bpy)](PF6) (1), indicating the suitability for photocatalytic H-2 evolution reaction. (MLCT)-M-3 emissions of both IbPE and 1pPE were quenched by electron transfer from triethylamine (TEA) sacrificial electron donor, but the quenching rate of IpPE was lower than that of nonmodified complex 1 and 1bPE. In contrast, the quenching rate of IbPE by an electron-accepting [Co (bpy)(3)](2+) moiety was slightly lower than 1 or IpPE. These results suggest that the two diethylphosphonate ester groups regulate the direction of photoinduced electron-transfer reaction at the (MLCT)-M-3 excited state due to their steric bulkiness. In addition, the photocatalytic activity for H-2 evolution in the presence of K2PtC14 precatalyst clearly showed remarkably extended longevity for both IpPE and 1bPE compared to that of 1, indicating that the two diethyl phosphonate groups attached on IpPE and IbPE also play an important role in the extended longevity of H-2-evolution activity of in-situ generated Pt colloidal catalyst from K2PtC14. The deactivation pathway of IpPE and 1bPE during photo H-2 evolution reaction is mainly due to the substitution of the bpy-type ligand by CH3CN solvent of the one electron reduced Ir(II) species like the non-substituted complex 1. (C) 2017 Elsevier B.V. All rights reserved.
  • Miho Isegawa, W. M. C. Sameera, Akhilesh K. Sharma, Taku Kitanosono, Masako Kato, Shu Kobayashi, Keiji Morokuma
    ACS CATALYSIS 7 (8) 5370 - 5380 2155-5435 2017/08 [Refereed][Not invited]
     
    We present a mechanistic survey on the LCu-catalyzed (L = chiral 2,2'-bipyridine ligand) enantioselective boron conjugate addition reaction, carried out using density functional theory (DFT) and artificial force induced reaction (AFIR) methods. The computed catalytic cycle for Cu(I)- and Cu(II)-based catalysts consists of three steps: (a) boron boron bond cleavage of B-2(pin)(2), (b) boron conjugate addition on the beta carbon of chalcone, and (c) protonation. The enantioselectivity of the reaction with LCuI or LCuII catalysts is solely governed at the boron conjugate addition step. The multicomponent(MC)-AFIR search and the subsequent DFT calculations for the LCuI catalyst determined transition states (TSs), which lead to Cu-I-O-enolate and Cu-I-C-enolate, and both equally contribute to the C-B bond formation with no enantioselectivity. On the other hand, a MC-AFIR search and the subsequent DFT calculations for the analogous LCuII catalyst showed that only the transition state (TS) leading to Cu-II-O-enolate contributes to the reaction. Furthermore, the TSs leading to the R and S forms of Cu-II-O-enolates are energetically well separated, with the R form being of lower energy, which is consistent with experimental observations. Our study provides important mechanistic insights for designing transition-metal catalysts for Cu-catalyzed enantioselective boron conjugate addition reactions.
  • Sogo Furugori, Atsushi Kobayashi, Ayako Watanabe, Masaki Yoshida, Masako Kato
    ACS Omega 2 (7) 3901 - 3912 2470-1343 2017/07/31 [Refereed][Not invited]
     
    To improve the efficiency of photoinduced charge separation on the surface of dye-sensitized TiO2 nanoparticles, we synthesized the Ru(II)-photosensitizer-immobilized, Pt-cocatalyst-loaded TiO2 nanoparticles RuCP2@Pt-TiO2, RuCP2-Zr-RuP6@Pt-TiO2, and RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2 (RuCP2 = [Ru(bpy)2(mpbpy)]2-, RuP4 = [Ru(bpy)(pbpy)2]6-, RuP6 = [Ru(pbpy)3]10-, H4mpbpy = 2,2′-bipyridine-4,4′-bis(methanephosphonic acid), and H4pbpy = 2,2′-bipyridine-4,4′-bis(phosphonic acid)) using phosphonate linkers with bridging Zr4+ ions. X-ray fluorescence and ultraviolet-visible absorption spectra revealed that a layered molecular structure composed of Ru(II) photosensitizers and Zr4+ ions (i.e., RuCP2-Zr-RuP6 and RuCP2-Zr-RuP4-Zr-RuP6) was successfully formed on the surface of Pt-TiO2 nanoparticles, which increased the surface coverage from 0.113 nmol/cm2 for singly layered RuCP2@Pt-TiO2 to 0.330 nmol/cm2 for triply layered RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2. The photocatalytic H2 evolution activity of the doubly layered RuCP2-Zr-RuP6@Pt-TiO2 was three times higher than that of the singly layered RuCP2@Pt-TiO2, whereas the activity of triply layered RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2 was less than half of that for RuCP2@Pt-TiO2. The photosensitizing efficiencies of these Ru(II)-photosensitizer-immobilized nanoparticles for the O2 evolution reaction catalyzed by the Co(II)-containing Prussian blue analogue [CoII(H2O)2]1.31[{CoIII(CN)6}0.63{PtII(CN)4}0.37] decreased as the number of Ru(II)-photosensitizing layers increased. Thus, crucial aspects of the energy- and electron-transfer mechanism for the photocatalytic H2 and O2 evolution reactions involve not only the Ru(II)-complex-TiO2 interface but also the multilayered structure of the Ru(II)-photosensitizers on the Pt-TiO2 surface.
  • Sogo Furugori, Atsushi Kobayashi, Ayako Watanabe, Masaki Yoshida, Masako Kato
    ACS Omega 2 (7) 3901 - 3912 2470-1343 2017/07/31 [Refereed][Not invited]
     
    To improve the efficiency of photoinduced charge separation on the surface of dye-sensitized TiO2 nanoparticles, we synthesized the Ru(II)-photosensitizer-immobilized, Pt-cocatalyst-loaded TiO2 nanoparticles RuCP2@Pt-TiO2, RuCP2-Zr-RuP6@Pt-TiO2, and RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2 (RuCP2 = [Ru(bpy)2(mpbpy)]2-, RuP4 = [Ru(bpy)(pbpy)2]6-, RuP6 = [Ru(pbpy)3]10-, H4mpbpy = 2,2′-bipyridine-4,4′-bis(methanephosphonic acid), and H4pbpy = 2,2′-bipyridine-4,4′-bis(phosphonic acid)) using phosphonate linkers with bridging Zr4+ ions. X-ray fluorescence and ultraviolet-visible absorption spectra revealed that a layered molecular structure composed of Ru(II) photosensitizers and Zr4+ ions (i.e., RuCP2-Zr-RuP6 and RuCP2-Zr-RuP4-Zr-RuP6) was successfully formed on the surface of Pt-TiO2 nanoparticles, which increased the surface coverage from 0.113 nmol/cm2 for singly layered RuCP2@Pt-TiO2 to 0.330 nmol/cm2 for triply layered RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2. The photocatalytic H2 evolution activity of the doubly layered RuCP2-Zr-RuP6@Pt-TiO2 was three times higher than that of the singly layered RuCP2@Pt-TiO2, whereas the activity of triply layered RuCP2-Zr-RuP4-Zr-RuP6@Pt-TiO2 was less than half of that for RuCP2@Pt-TiO2. The photosensitizing efficiencies of these Ru(II)-photosensitizer-immobilized nanoparticles for the O2 evolution reaction catalyzed by the Co(II)-containing Prussian blue analogue [CoII(H2O)2]1.31[{CoIII(CN)6}0.63{PtII(CN)4}0.37] decreased as the number of Ru(II)-photosensitizing layers increased. Thus, crucial aspects of the energy- and electron-transfer mechanism for the photocatalytic H2 and O2 evolution reactions involve not only the Ru(II)-complex-TiO2 interface but also the multilayered structure of the Ru(II)-photosensitizers on the Pt-TiO2 surface.
  • Masanori Wakizaka, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Ho-Chol Chang
    CHEMISTRY-A EUROPEAN JOURNAL 23 (41) 9919 - 9925 0947-6539 2017/07 [Refereed][Not invited]
     
    The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metaland/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N](3)fac-[CrIII(mp)(3)] (1) (mp= 2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, and its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. Since complex 1 contains O/S coordination sites in three directions, complexation with K+ ions led to the formation of the two-dimensional honeycomb sheet-structured [K(3)fac{ Cr-III(mp)(3)}(H2O)(6)] n (2.6H(2)O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML within the CN 2.6H(2)O in the solid state.
  • Tatsuya Hasegawa, Atsushi Kobayashi, Hiroki Ohara, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 56 (9) 4928 - 4936 0020-1669 2017/05 [Refereed][Not invited]
     
    We have synthesized two luminescent mononuclear Cu(I) complexes, [Cu(PPh(2)Tol)(THF)(4Mepy)(2)](BF4) (1) and [Cu-(PPh(2)Tol) (4Mepy)(3)] (BF4) (2) (PPh(2)Tol = diphenyl(o-tolyl)phosphine, 4Mepy = 4-methylpyridine, THF = tetrahydrofuran), and investigated their crystal structures, luminescence properties, and vapor-induced ligand exchange reactions in the solid state. Both coordination complexes are tetrahedral, but one of the three 4Mepy ligands of complex 2 is replaced by a THF solvent molecule in complex 1. In contrast to the very weak blue emission of the THF-bound complex 1 (wavelength of emission maximum (lambda(em)) = 457 nm, emission quantum yield (Phi(em)) = 0.02) in the solid state at room temperature, a very bright blue-green emission was observed for 2 (lambda(em) = 484 rim, Phi(em) = 0.63), suggesting a contribution of the THF ligand to nonradiative deactivation. Time dependent density functional theory calculations and emission lifetime measurements suggest that the room-temperature emissions of the complexes are due to thermally activated delayed fluorescence from the metal-to-ligand charge transfer excited state. Interestingly, by exposing the solid sample of THF-bound 1 to 4Mepy vapor, the emission intensity drastically increased and the emission color changed from blue to blue-green. Powder X-ray diffraction measurements revealed that the emission change of 1 is due to the vapor-induced ligand exchange of THF for 4Mepy, forming the strongly emissive complex 2. Further emission tuning was achieved by exposing 1 to pyrimidine or pyrazine vapors, forming green (lambda(em) = 510 nm) or orange (lambda(em) = 618 rim) emissive complexes, respectively. These results suggest that the vapor-induced ligand exchange is a promising method to control the emission color of luminescent Cu(I) complexes.
  • Atsushi Kobayashi, Ryuya Arata, Tomohiro Ogawa, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 56 (8) 4280 - 4288 0020-1669 2017/04 [Refereed][Not invited]
     
    Two luminescent pyrazine-bridged dinuclear Cu(I) complexes, namely, [{Cu(PPh3)(2)(H2O)}(mu-MeOpyz){ Cu (PPh3)(2)(CH3CN)}] (BF4)(2) and [{Cu (PPh3)(2)(H2O)} (mu-MeOpyz){Cu(PPh3)(2)(H2O)}] (BF4)(2)(H2O-Cu(2-)AN PPh3 = triphenylphosphine, MeOpyz = 2-methoxypyrazine), were successfully synthesized and characterized by single-crystal X-ray diffraction and luminescence measurements. X-ray analysis revealed that the water molecules are coordinated to both Cu(I) ions to form almost the same P2N1O1 coordination structure in H2O-Cu-2-H2O, whereas one of the two Cu ions in H2O-Cu-2-AN was coordinated by acetonitrile instead of water to form a different P2N2 coordination environment. The asymmetric H2O-Cu-2-AN exhibits very bright yellow-green emission with a high emission quantum yield (lambda(em) = 550 nm, Phi= 0.70) at room temperature in the solid state in spite of the coordination of water molecule, which usually tends to deactivate the emissive state through O H vibration. The intense emission at room temperature is a result of thermally activated delayed fluorescence, and the remarkable temperature dependence of emission lifetimes indicates the existence of unique multiple emission states for the asymmetric dinuclear complex. In contrast, the emission of H2O-Cu-2-H2O was observed at longer wavelengths with remarkably a lower quantum yield (lambda(em) = 580 nm, Phi = 0.05). Time-dependent density functional theory calculations suggested that the emission could result from the metal-to-ligand charge-transfer transition state. However, it could be rapidly deactivated by the structural distortion around the Cu ion with a less-bulky coordination environment in H2O-Cu-2-H2O.
  • Indranil Chakraborty, Jorge Jimenez, W. M. C. Sameera, Masako Kato, Pradip K. Mascharak
    INORGANIC CHEMISTRY 56 (5) 2863 - 2873 0020-1669 2017/03 [Refereed][Not invited]
     
    A family of Re(I) carbonyl complexes of general formula [ReX(CO)(3)(phen)(0/1+) (where X = Cl-, CF3SO3-, MeCN, PPh3, and methylimidazole) derived from 1,10-phenanthroline (phen) exhibits variable emission characteristics depending on the presence of the sixth ancillary ligand/group (X). All complexes but with X = MeCN exhibit moderate CO release upon irradiation with low-power UV light and are indefinitely stable in anaerobic/aerobic environment in solution as well as in solid state when kept under dark condition. These CO donors liberate three, one, or no CO depending on the nature of sixth ligand upon illumination as studied with the aid of time-dependent IR spectroscopy. Results of excited-state density functional theory (DFT) and time-dependent DFT calculations provided insight into the origin of the emission characteristics of these complexes. luminescent rheinum(I) photoCORMs uniformly displayed efficient cellular internalization by the human breast adenocarcinoma cells, MDA-MB-231, while the complex with PPh3 as ancillary ligand showed moderate nuclear localization in addition to the cytosolic distribution. These species hold significant promise as theranostic photoCORMs (photoinduced CO releasing molecules), where the entry of the pro-drug can be tracked within the cellular matrices.
  • Ayako Watanabe, Atsushi Kobayashi, Erika Saitoh, Yuki Nagao, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa, W. M. C. Sameera, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 56 (5) 3005 - 3013 0020-1669 2017/03 [Refereed][Not invited]
     
    We synthesized two new porous coordination polymers (PCPs) {Ln(7)(OH)(5)[Ru(dcbpy)(3)](4).4nH(2)O} (Ln(7)-Ru-4; Ln = Ce, Nd) composed of the luminescent ruthenium (II) metalloligand [Ru(4,4'-dcbpy)(3)](4-) ([4Ru]; 4,4'-dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and lanthanide ions Ln(3+) (Ln = Ce, Nd). These two PCPs Ln7-Ru4 are isomorphous with the previously reported PCP La-7-Ru-4, and the lattice constants (a, c, and unit cell volume V) changed systematically according to the lanthanide contraction. All three Ln(7)-Ru-4 compounds have OW anion containing porous structures and a large number of hydrate water molecules within the pores, resulting in moderate ion conductivities (10(-6)-10(-7) S cm(-1)) at 90% relative humidity Wavelength / nm (RH) and 298 K. In contrast, the structural transformation of Ln(7)-Ru-4 associated with water-vapor adsorption/desorption strongly depends on the lanthanide ion; the Ln(7)-Ru-4 compounds with larger Ln(3+) ions recover the original porous structure at lower relative humidities (RH). A similar trend was observed for the ion conduction activation energy, suggesting that the bridging Ln(3+) ion plays an important role in the formation of the ion conductive pathways. La-7-Ru-4 and Ce-7-Ru-4 exhibit vapochromic luminescence associated with water vapor adsorption/desorption, arising from the (MLCT)-M-3 emission of [4Ru]. This vapochromic behavior is also affected by the replacement of the Ln3(+) ion; the vapochromic shift of Ce-7-Ru-4 was observed at RH values (near 100% RH) higher than that of La-7-Ru-4. (MLCT)-M-3 emissions of the [4Ru] metalloligand in Nd-7-Ru-4 were barely observable in the visible region, but sharp emission bands characteristic of 4f-4f transitions of the Nd3+ ion were observed in the near -infrared (NIR) region (arising from the (MLCT)-M-1 transition of [4Ru]), suggesting the transfer of energy from the [4Ru] (MLCT)-M-3 excited state to the 4f-4f transition state of the Nd3+ ions.
  • Hiroki Ohara, Tomohiro Ogawa, Masaki Yoshida, Atsushi Kobayashi, Masako Kato
    DALTON TRANSACTIONS 46 (11) 3755 - 3760 1477-9226 2017/03 [Refereed][Not invited]
     
    [CuCl(PPh3)(2)(4-Mepy)] (PPh3 = triphenylphosphine, 4-Mepy = 4-methylpyridine), a highly blue-luminescent mononuclear copper(I) complex, shows reversible emission colour change ranging from blue-green to red by vapour exposure to N-heteroaromatics, such as pyridine, pyrimidine, and 2-methylpyrazine. The remarkable colour changes occur due the ligand exchange reaction between the solid and gas. Such ligand exchange reactions would be applicable to various vapours with coordination ability and be useful for the sensing of such volatile organic compounds as well as a new convenient methodology for the preparation of luminescent complexes.
  • Paramita Kar, Masaki Yoshida, Yasuhiro Shigeta, Akane Usui, Atsushi Kobayashi, Takaaki Minamidate, Noriaki Matsunaga, Masako Kato
    Angewandte Chemie Wiley 129 (9) 2556  2017/02 [Refereed][Not invited]
  • Paramita Kar, Masaki Yoshida, Yasuhiro Shigeta, Akane Usui, Atsushi Kobayashi, Takaaki Minamidate, Noriaki Matsunaga, Masako Kato
    Angewandte Chemie Wiley 129 (9) 2385  2017/02 [Refereed][Not invited]
  • Paramita Kar, Masaki Yoshida, Yasuhiro Shigeta, Akane Usui, Atsushi Kobayashi, Takaaki Minamidate, Noriaki Matsunaga, Masako Kato
    Angewandte Chemie International Edition Wiley 56 (9) 2514  2017/02 [Refereed][Not invited]
  • Paramita Kar, Masaki Yoshida, Yasuhiro Shigeta, Akane Usui, Atsushi Kobayashi, Takaaki Minamidate, Noriaki Matsunaga, Masako Kato
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 56 (9) 2345 - 2349 1433-7851 2017/02 [Refereed][Not invited]
     
    A highly methanol-selective vapochromic response has been realized in a Ni-II-quinonoid complex, [Ni(HLMe)(2)] (H2LMe=4-methylamino-6-methyliminio-3-oxocyclohexa-1,4-dien-1-olate) which exhibits a reversible structural transformation including a coordination geometrical change between the square-planar and octahedral structure by the selective uptake of methanol vapor. This was accompanied by a remarkable color change between purple and orange, as well as temperature-robust spin-state switching in the solid state under ambient conditions. It is remarkable that the properties are derived by the fine structural modification of the quinonoid ligand such as methyl or ethyl analogues. Such a system has high potential for applications in memory devices as well as chemical sensors and smart responsive materials.
  • Atsushi Kobayashi, Masako Kato
    CHEMISTRY LETTERS 46 (2) 154 - 162 0366-7022 2017/02 [Refereed][Not invited]
     
    Extensive studies of luminescent copper(I) complexes were conducted, revealing that some of them exhibit interesting chromic luminescence in response to external stimuli such as temperature, vapor, light, and mechanical force. In this review, recent progress in the field of luminescent chromic copper(I) complexes is discussed. Tetranuclear copper(I) clusters with a cubane-type {Cu4I4} core are the most prominent group, which shows thermochromic, vapochromic, and mechanochromic luminescence, and their responsiveness to external stimuli greatly depends on coordinating organic ligands. Coordination polymerization of copper(I) cluster cores using organic linkers provides new luminescent thermochromic and vapochromic materials with behavior strongly dependent on the flexibility of the framework. The diversity of the cluster core structure and the lability to the ligand exchange are also useful to derive unique behaviors of photochromic and vapochromic response. In addition to such stimuli-responsive luminescence, the mechanochemical synthesis of highly luminescent copper(I) complexes is introduced, since the phenomenon is closely related to the mechanochromic luminescence and this approach allows the preparation of an emission layer directly on the substrate.
  • Kana Sawaguchi-Sato, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 335 182 - 189 1010-6030 2017/02 [Refereed][Not invited]
     
    We have synthesized CdSe (cadmium selenide) quantum dots (QDs) with three different surface-passivating ligands: 3-mercaptopropionic acid (MPA), 4-mercaptobenzoic acid (MBA), and 4-mercaptomethylbenzoic acid (MMBA). Although all the QDs possessed similar diameters and thiol-based ligands, the MPA-passivated QD exhibited the highest photocatalytic H2 evolution activity in the presence of a polyvinylpyrrolidone-protected Pt (Pt-PVP) colloidal catalyst. Moreover, dynamic light scattering and zeta potential measurements clearly indicated a significant difference in their dispersibility in water. Thus, CdSe-MPA, having the sterically smallest thiol ligand, displayed the largest negative zeta potential and the best dispersibility owing to the presence of negatively charged carboxylate groups on the QD surface. This was sufficient for the QD to disperse as single particles. In contrast, the bulkier MMBA ligand covered the surface of the CdSe QD with a smaller number of ligand moieties, resulting in a smaller zeta potential and the formation of large aggregates (similar to 126 nm in diameter). In the presence of a Pt-PVP colloid as the hydrogen evolution catalyst, CdSe-MPA formed large aggregates (similar to 1.6 mu m in diameter) with the Pt-PVP colloid by electrostatic interactions. Conversely, CdSe-MMBA did not form such large aggregates with the Pt-PVP colloid. Since the emission of the CdSe QD was effectively quenched in the presence of the Pt-PVP colloid, we concluded that CdSe-MPA exhibits the highest photocatalytic hydrogen evolution activity with the Pt-PVP colloidal catalyst because the electron transfer efficiency from the photosensitizing CdSe QD to the Pt-PVP colloidal catalyst is enhanced by the formation of aggregates. (C) 2016 Elsevier B.V. All rights reserved.
  • Erika Saitoh, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    CRYSTAL GROWTH & DESIGN 16 (12) 7051 - 7057 1528-7483 2016/12 [Refereed][Not invited]
     
    In this study, we examined the reduction in crystal size of the porous coordination polymers (PCPs) {Sr-4(H2O)(9)][4Ru](2)center dot 9H(2)O]} (Sr-2[4Ru]) and [Mg(H2O)(6)]-{[Mg, (H2O)(3)[4Ru]center dot 4H(2)O} (Mg-2[4Ru]) composed of a luminescent metalloligand [Ru(4,4'-dcbpy)](4-) ([4Ru]; 4,4'= 4,4'-dicarboxy-2,2'-bipyridine) using a coordination modulation method. Scanning electron microscopy measurements clearly show that the sizes of crystals of Sr-2[4Ru] and Mg-2[4Ru] were successfully reduced to the mesoscale (about 500 nm width and 10 nm thickness for Sr-2[4Ru] (abbreviated as m-Sr-2[4Ru]) and about 1 mu m width and 30 nm thickness for Mg-2[4Ru] (abbreviated as m-Mg-2[4Ru])) using lauric acid as a coordination modulator. Interestingly, the nanocrystals of m-Sr-2[4Ru] formed flower-like aggregates with diameters of 1 mu m, whereas flower-like aggregates were not formed in m-Mg-2[4Ru]. Water vapor adsorption isotherms of these nanocrystals suggest that the water adsorption behavior of m-Sr-2[4Ru], which has a three-dimensional lattice structure containing small pores, is significantly different from that of the bulk Sr-2[4Ru] crystal, as shown by the vapor adsorption isotherm. In contrast, m-Mg-2[4Ru], which has a two-dimensional sheet structure, had an adsorption isotherm very similar to that of the bulk sample. These contrasting results suggest that the dimensionality of the coordination framework is an important factor for the guest adsorption behavior of nanocrystalline PCPs.
  • Hua-Xin Zhang, Yukihisa Okawa, Masako Kato, Yoichi Sasaki, Kohei Uosaki
    JOURNAL OF ELECTROANALYTICAL CHEMISTRY 781 41 - 47 1572-6657 2016/11 [Refereed][Not invited]
     
    Novel electrocatalysts for methanol oxidation were prepared from two Pt-Ni multinuclear complexes, [Pt-2{Ni(NH2CH2CH2S)(2)}(4)]Cl-4 and [Pt(bpy){Ni(NH2CH2CH2S)(2)(bpy)}](NO3)(2) (bpy = 2,2'-bipyridine). They were adsorbed on a Au(111) surface by immersing the Au(111) electrode in solutions containing these complexes. The modified Au(111) electrodes were then subjected to potential cycling or heat-treatment at 200 degrees C and 300 degrees C so that organic ligands were decomposed and adsorbed complexes were converted to nanocomposites. For a comparison, Au(111) electrode modified by a Pt based nanocomposite prepared by using a di-platinum(II) complex ([Pt-2(terpy)(2)(mu-otdst)](2+) (terpy = 2.2':6',2 ''-terpyridine, H(2)otdst = 2-octylthio-4,6-disulfanyl-1,3,5-triazine)) as a starting molecule. The surface species were characterized by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) in addition to cyclic voltammetry (CV). Two-dimensional nano composites of monatomic height were observed by STM. The coverages of the nanocomposites were 2-8%. By repeating the complex adsorption and heat-treatment for five times, nanocomposites of higher coverage of 13-19% with monatomic height were formed on Au(111) surface. The resultant nanocomposites showed high activity for methanol oxidation reaction (MOR) with an improved CO-tolerance in a 0.1 M KOH aqueous solution containing 1 M CH3OH. (C) 2016 Elsevier B.V. All rights reserved.
  • Kotaro Shimada, Atsushi Kobayashi, Yuriko Ono, Hiroki Ohara, Tatsuya Hasegawa, Tetsuya Taketsugu, Eri Sakuda, Soichiro Akagi, Noboru Kitamura, Masako Kato
    JOURNAL OF PHYSICAL CHEMISTRY C 120 (29) 16002 - 16011 1932-7447 2016/07 [Refereed][Not invited]
     
    Thiolato-bridged dinuclear, tetranuclear, and hexanuclear Cu(I) complexes [Cu-2(P boolean AND S)(2)(PPh3)(2)], [Cu-4(P boolean AND S)(4)(CH3CN)(2)], and [Cu-6(P boolean AND S)(6)] (abbreviated as Cu-2, Cu-4, and Cu-6, respectively, P boolean AND S = 2-(diphenylphosphino)benzenethiolate, PPh3 = triphenylphosphine) were synthesized and characterized by elemental analyses and single-crystal X-ray diffraction measurements. These complexes had {Cu2S2}, {Cu4S4}, and {Cu6S6} cluster cores and exhibited strong luminescence at room temperature in solid states. Different luminescence properties were observed depending on the core structure. Cu-2, Cu-4, and Cu-6 exhibited blue-green (lambda(max) = 482 nm, Phi(em) = 0.52), green (lambda(max) = 526 nm, Phi(em) = 0.19), and yellow (lambda(max) = 553 nm, Phi(em) = 0.49) luminescence, respectively, at 298 K in the solid state; among them, only Cu6 showed luminescence thermochromism. Different radiative rate constants at room temperature and 78 K derived from the emission lifetimes and quantum yields indicate that the luminescence from Cu-2 and Cu-4 at room temperature originated from thermally activated delayed fluorescence (TADF), whereas the luminescence at low temperatures was attributed to the phosphorescence. The temperature dependence of the emission lifetimes was successfully analyzed by the singlettriplet two-state model with an energy difference (Delta ES1-T1) of 547 and 775 cm(-1) for Cu-2 and Cu-4, respectively. Based on the time-dependent density-functional theory calculations, the origin of the luminescence for Cu-2 and Cu-4 was attributed to the charge transfer from the cluster core to the ligand. Moreover, the small values of Delta ES1-T1 for Cu-2 and Cu-4 were supported by the excited state calculations. On the other hand, the emission origin of Cu-6 was attributed to the phosphorescence from the triplet cluster-centered (3CC) excited state in which the electron is located on a bonding in-phase orbital constructed from the 4s/4p orbitals of the Cu atoms because only Cu6 contains trigonal-planar Cu(I) ions in the cluster.
  • Yuka Okano, Hiroki Ohara, Atsushi Kobayashi, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 55 (11) 5227 - 5236 0020-1669 2016/06 [Refereed][Not invited]
     
    We have newly synthesized two solution-stable luminescent dinuclear copper(I) complexes, [Cu-2(mu-I)(2)(dpppy)(2)] (Cu-py) and [Cu-2(mu-I)(2)(dpppyz)(2)] (Cu-pyz), where dpppy = 2,3-bis(diphenylphosphino)pyridine and dpppyz = 2,3-bis(diphenylphosphino)pyrazine, using chelating diphosphine ligands composed of N-heteroaromatic rings. X-ray analysis clearly indicates that the molecular structures of Cu-py and Cu-pyz are almost identical with that of the parent complex, [Cu-2(mu-I)(2)(dppb)(2)] [Cu-bz; dppb = 2,3-bis(diphenylphosphino)benzene]. Complexes Cu-py and Cu-pyz exhibit luminescence [emission quantum yield (Phi(em)) = 0.48 and 0.02, respectively] in the solid state at 298 K. A wide emission color tuning, from 497 to 638 nm (energy = 0.55 eV, with an emission color ranging from green to reddish-orange), was achieved in the solid state by the introduction of pyridinic N atoms into the bridging phenyl group between the two diphenylphosphine groups. Density functional theory calculations suggest that the emission could originate from the effective combination of the metal-to-ligand charge-transfer excited state with the halide-to-ligand charge-transfer excited state. Thus, the emission color change is due to stabilization of the pi* levels of the central aryl group in the diphosphine ligand. Furthermore, these copper(I) complexes exhibit thermally activated delayed fluorescence at 298 K because of the small singlet-triplet energy difference (Delta E = 523 and 564 cm(-1) for Cu-py and Cu-pyz, respectively). The stability of these complexes in chloroform, due to the rigid bonds between the diphosphine ligands and the Cu-I ions, enables the preparation of emissive poly(methyl methacrylate) films by the solution-doping technique.
  • Atsushi Kobayashi, Sogo Furugori, Masaki Yoshida, Masako Kato
    CHEMISTRY LETTERS 45 (6) 619 - 621 0366-7022 2016/06 [Refereed][Not invited]
     
    We synthesized a novel tris(bipyridyl)Ru(II) complex with sulfonic acid groups, [Ru(dSbpy)(bpy)(2)] (RuCS2; H(2)dSbpy: 2,2'-bipyridine-4,4'-bis(methanesulfonic acid)). The photosensitizing efficiency of water oxidation in the presence of a Na2S2O8 sacrificial electron acceptor was higher than that of the widely used phosphonic acid analog, [Ru(H(4)dPbpy)(bpy)(2)]Cl-2 (RuCP2; H(4)dPbpy: 2,2'-bipyridine-4,4'-bis(methanephosphonic acid)). The photosensitizing efficiency of RuCP2 for water oxidation was remarkably enhanced by immobilization onto semiconducting TiO2 nanoparticles.
  • Atsushi Kobayashi, Tatsuya Hasegawa, Masald Yoshida, Masako Kato
    INORGANIC CHEMISTRY 55 (5) 1978 - 1985 0020-1669 2016/03 [Refereed][Not invited]
     
    Luminescent dinuclear Cu(I) complexes, [Cu2X2(dpypp)(2)] [Cu-X; X = Cl, Br, I; dpypp = 2,2'(phenylphosphinediyl)dipyridine], were successfully synthesized by a solvent-assisted mechanochemical method. A trace amount of the assisting solvent plays a key role in the mechanochemical synthesis; only two solvents possessing the nitrile group, CH3CN and PhCN, were effective for promoting the formation of dinuclear Cu-X. X-ray analysis revealed that the dinuclear structure with no Cu center dot center dot center dot Cu interactions, bridged by two dpypp ligands, was commonly formed in all Cu-X species. These complexes exhibited bright green emission in the solid state at room temperature (phi = 0.23, 0.50, and 0.74; lambda(em) = 528, 518, and 530 nm for Cu-Cl, Cu-Br, and Cu-I, respectively). Emission decay measurement and TD-DFT calculation suggested that the luminescence of Cu-X could be assigned to phosphorescence from the triplet metal-to-ligand charge-transfer ((MLCT)-M-3) excited state, effectively mixed with the halide-to-ligand charge-transfer ((XLCT)-X-3) excited state, at 77 K. The source of emission changed to thermally activated delayed fluorescence (TADF) with the same electronic transition nature at room temperature. In addition, the CH3CN-bound analogue, [Cu-2(CH3CN)(2)(dpypp)(2)](BF4)(2), was successfully mechanochemically converted to Cu-X by grinding with solid KX in the presence of a trace amount of assisting water.
  • Yasuhiro Shigeta, Atsushi Kobayashi, Tadashi Ohba, Masaki Yoshida, Takeshi Matsumoto, Ho-Chol Chang, Masako Kato
    CHEMISTRY-A EUROPEAN JOURNAL 22 (8) 2682 - 2690 0947-6539 2016/02 [Refereed][Not invited]
     
    A novel platinum(II)-diimine complex, [Pt(CN)(2)(H(2)dcphen)] (1; H(2)dcphen=4,7-dicarboxy-1,10- phenanthroline), was synthesized and its vapochromic shape-memory behavior was evaluated. The as-synthesized amorphous purple solid, [Pt(CN)(2)(H(2)dcphen)]2H(2)O (1P), exhibited vapochromic behavior in the presence of alcoholic vapors through transformation to a red, crystalline, porous, vapor-adsorbed form, 1Rvapor. The obtained 1Rvapor complex released the adsorbed vapors upon heating without collapse of the porous structure. The vaporfree, porous 1Ropen could detect water or n-hexane vapor, although these vapors could not induce 1P-to-1Rvapor transformation, and 1Ropen could easily be converted to the initial 1P by manual grinding. These results indicate that 1 is a new shape-memory material that functions through formation and collapse of the porous framework with an emission change upon vapor-adsorption and grinding; this enables it to exhibit vapor history and ON-OFF switching sensing functions.
  • Atsushi Kobayashi, Shiori Oizumi, Yasuhiro Shigeta, Masaki Yoshida, Masako Kato
    DALTON TRANSACTIONS 45 (43) 17485 - 17494 1477-9226 2016 [Refereed][Not invited]
     
    We synthesized a carboxy-substituted Pt(II)-terpyridine complex, i.e. [PtCl(Hctpy)] Cl ([1H] Cl; Hctpy = 4'-carboxy-2,2': 6',2''-terpyridine), that shows interesting switchable vapochromic behaviour upon protonation/deprotonation of the carboxy group. The as-synthesized dark-blue amorphous-like solid [1H] Cl center dot 3H(2)O was converted to a yellow crystalline solid, [1H] Cl center dot H2O, upon exposure to various polar organic solvent vapours (e.g., acetonitrile, ethanol, 1-propanol, and dichloromethane), which promote the removal of water molecules. The reaction of [1H] Cl center dot 3H(2)O with aqueous ammonia afforded a deprotonated bright-yellow crystalline complex, i.e. [PtCl(ctpy)]center dot H2O (1 center dot H2O), which exhibits red luminescence with an emission maximum at 622nm. Although the colour of 1 center dot H2O was not affected by exposure to various polar organic solvent vapours, interesting vapochromic luminescence with a remarkable red-shift of the emission maximum from 622 to 652 nm was observed upon exposure to saturated water vapour to form orange crystalline 1 center dot 3.5H(2)O X-ray structural analysis revealed that the planar and neutral complex molecule 1 forms a one-dimensional columnar structure with an intermolecular Pt center dot center dot center dot Pt distance of 3.518(2) angstrom in the orange crystall 1 center dot 3.5H(2)O, while the cationic molecule [1H](+) in the protonated form, [1H] Cl center dot H2O, generates a dimeric structure with an intermolecular Pt center dot center dot center dot Pt distance of 3.439(2) angstrom. This difference suggests that the vapochromic behaviours of the protonated and deprotonated forms could be caused by structural changes induced by water-vapour adsorption/desorption, which affect the intermolecular Pt. Pt distance, thereby changing the energy of the metal-metal-to-ligand charge-transfer (MMLCT) transition. These contrasting results for the protonated and deprotonated complexes clearly indicate that the hydrophilicity of complex 1 is significantly affected by protonation/deprotonation of the carboxy group. In addition, quasi-reversible conversion between [1H] Cl center dot 3H(2)O and 1 center dot H2O was achieved by exposure of the protonated and deprotonated forms to triethylamine and humid hydrochloric acid vapours, respectively.
  • Kiyoshi Tsuge, Yuko Chishina, Hanako Hashiguchi, Yoichi Sasaki, Masako Kato, Shoji Ishizaka, Noboru Kitamura
    COORDINATION CHEMISTRY REVIEWS 306 (P2) 636 - 651 0010-8545 2016/01 [Refereed][Not invited]
     
    Neutral halogenido copper(l) units {CunXn} are widely found in the luminescent copper(l) complexes. In this review, we describe the luminescent properties of complexes with the halogenido-bridged dimeric core, {Cu-2(mu-X)(2)}, which is one of the basic structural motifs of {CunXn}, as well as their synthetic methods and structural features. The available emissive excited states and their approximate energies are discussed by comparing the emission energies among the complexes with different ligand combinations. The trend of the quantum yields in the {Cu2X2} complexes will also be discussed. (C) 2015 Elsevier B.V. All rights reserved.
  • Paramita Kar, Masaki Yoshida, Atsushi Kobayashi, Lucie Routaboul, Pierre Braunstein, Masako Kato
    DALTON TRANSACTIONS 45 (36) 14080 - 14088 1477-9226 2016 [Refereed][Not invited]
     
    The stepwise reaction of a zwitterionic ligand, 4-methylamino-6-methyliminio-3-oxocyclohexa-1,4-dien-1-olate (QH(2)) with [Pt-2(mu-Cl)(2)(ppy)(2)] (Hppy = 2-phenylpyridine) afforded a mononuclear complex, [Pt(ppy)(QH)] (1), and a dinuclear complex, [{Pt(ppy)}(2)(mu-Q)] (2). Using [ Pd-2(mu-Cl)(2)(ppy)(2)] in the second step resulted in the formation of a heterodinuclear complex, [{Pt(ppy)}(mu-Q){Pd(ppy)}] (3), which is the first heterodinuclear complex bridged by a quinonoid ligand. Single crystal X-ray diffraction analysis revealed that all three complexes adopted double-decker structures in the crystal. For 1, intermolecular N-H center dot center dot center dot O interactions between uncoordinated N-H and O groups in two adjacent square-planar mononuclear units led to the formation of hydrogen-bonded dimers, which stacked to form a herringbone structure with a double-decker tetranuclear motif. For 2 and 3, dinuclear units bridged by Q(2) formed a double-decker motif similar to that of 1, but a tetranuclear chain in the herringbone pattern was characteristic of the dinuclear complexes. Pt. Pt (or Pt. Pd) distances were more than 3.5 angstrom, twice the van der Waals radii of Pt, suggesting weak electronic metal-metal interactions in the crystal structures. Thus, the different colours observed (brown, purple, and dark green for 1, 2, and 3, respectively) mainly originated from the molecular structures. In fact, the three complexes exhibited colourful solutions of yellow, red, and green. UV-vis absorption spectroscopy and time-dependent density-functional theory (TD-DFT) calculations revealed that colour variations occurred depending on the electronic states composed of metal ions and the quinonoid ligand.
  • Masaki Yoshida, Naoki Yashiro, Hotaka Shitama, Atsushi Kobayashi, Masako Kato
    CHEMISTRY-A EUROPEAN JOURNAL 22 (2) 491 - 495 0947-6539 2016/01 [Refereed][Not invited]
     
    A redox series of cyclometalated platinum complexes based on a dinuclear motif linked by acetamidato (aam) bridging ligands, [Pt-2(mu-aam)(2)(ppy)(2)] (ppy(-) = 2-phenylpyridinate ion), has been synthesized. The complexes in this series are easily oxidized and reduced by both electrochemical and chemical methods, and this is accompanied by multistep changes in their optical properties, that is, multiple color changes and luminescence. Isolation of the complexes and the structural determination of three oxidation states, +2, +2.33, and +3, have been achieved. The mixed-valent complex, with an average oxidation state of +2.33, forms a trimer based on the dinuclear motif. The mixed-valent complex has a characteristic color owing to intervalence transitions in the platinum chain. In contrast, the divalent complex exhibits strong red phosphorescence originating from a triplet metal-metal-toligand charge transfer ((MMLCT)-M-3) state. This study demonstrates the unique chromic behavior of a redox-active and luminescent platinum complex.
  • Masaki Yoshida, Show Ueno, Yuka Okano, Akane Usui, Atsushi Kobayashi, Masako Kato
    JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 313 99 - 106 1010-6030 2015/12 [Refereed][Not invited]
     
    A series of 3d transition-metal complexes bearing o-phenylenediamine (opda) ligands [M(opda)(3)](2+) (M = Mn2+, Co2+, Ni2+, and Zn2+) were systematically synthesized as perchlorate salts and their structures were determined. All the opda complexes exhibited hydrogen-evolving activities under photoirradiation conditions as in the case of previously reported [Fe(opda)(3)](2+), whereas replacement of the opda ligands with other aromatic amine ligands caused a dramatic decrease of hydrogen-evolving activities. These results support a ligand-based reaction mechanism for photochemical hydrogen evolution from [M(opda)(3)](2+), which involves (1)pi pi* excitation of the opda ligand followed by homolytic N-H bond cleavage. In contrast to the non-catalytic reactions, an obvious metal-ion dependency was observed for the catalytic systems including hydroquinone as a proton/electron donor. The results of this work demonstrate a strategy for the design of a molecular photochemical hydrogen-production system under ambient temperature and pressure. (C) 2015 Elsevier B.V. All rights reserved.
  • Ayako Watanabe, Atsushi Kobayashi, Erika Saitoh, Yuki Nagao, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 54 (23) 11058 - 11060 0020-1669 2015/12 [Refereed][Not invited]
     
    We synthesized a new porous coordination polymer {La-1.75(OH)(1.25)[RU(dcbpy)(3)]center dot 16H(2)O} (La-7-[4Ru](4); H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) composed of a luminescent ruthenium(II) metalloligand [Ru(4,4'-dcbpy)(3)](4-) and La3+ cations. X-ray analysis for La-7-[4Ru](4) revealed that the La3+ cations and [4Ru] metalloligands are crystallized in a molar ratio of 7:4 with OH- counteranions and a void fraction of similar to 25.5%. Interestingly, La-7-[4Ru](4) shows a reversible structural transition triggered by water ad/desorption, which affects not only the triplet metal-to-ligand charge-transfer ((MLCT)-M-3) emission energy but also the ion conductivity in the solid state. This correlation suggests that La-7-[4Ru](4) is an interesting material that enables visualization of the ion conductivity via the 3MLCT emission energy.
  • Takahiro Hayashi, Atsushi Kobayashi, Hiroki Ohara, Masaki Yoshida, Takeshi Matsumoto, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 54 (18) 8905 - 8913 0020-1669 2015/09 [Refereed][Not invited]
     
    Two luminescent porous coordination polymers (PCPs), i.e., [Cu-2(mu(2)-I)(2)ctpyz](n) and [Cu-4(mu(3)-I)(4)ctpyz](n) (Cu2 and Cu4, respectively; ctpyz = cis-1,3,5-cyclohexanetriyl-2,2',2 ''-tripyrazine), were successfully synthesized and characterized by single-crystal X-ray diffraction and luminescence spectroscopic measurements. Cu2 consists of rhombus-type dinuclear {Cu2I2} cores bridged by ctpyz ligands, while Cu4 is constructed of cubane-type tetranuclear {Cu4I4} cores bridged by ctpyz ligands. The void fraction of Cu4 is estimated to be 48.0%, which is significantly larger than that of Cu2 (19.9%). Under UV irradiation, both PCPs exhibit red luminescence at room temperature in the solid state (lambda(em) values of 660 and 614 nm for Cu2 and Cu4, respectively). Although the phosphorescence of Cu2 does not change upon removal and/or adsorption of EtOH solvent molecules in the porous channels, the solid-state emission maximum of Cu4 red-shifts by 36 run (lambda(em) = 650 nm) upon the removal of the adsorbed benzonitrile (PhCN) molecules from the porous channels (and vice versa). This large difference in the vapochromic behavior of Cu2 and Cu4 is closely related to the framework flexibility. The framework of Cu2 is sufficiently rigid to retain the porous structure without solvated EtOH molecules, whereas the porous structure of Cu4 collapses easily after removal of the adsorbed PhCN molecules to form a nonporous amorphous phase. The original vapor-adsorbed porous structure of Cu4 is regenerated by exposure of the amorphous solid to not only PhCN vapor but also tetrahydrofuran, acetone, ethyl acetate, and N,N-dimethylformamide vapors. The Cu4 structures with the various adsorbed solvents showed almost the same emission maxima as the original PhCN-adsorbed Cu4, except for DMF-adsorbed Cu4, which showed no luminescence probably because of weak coordination of the DMF vapor molecules to the Cu(I) centers of the tetranuclear {Cu4I4} core.
  • Masanori Ebina, Atsushi Kobayashi, Tomohiro Ogawa, Masaki Yoshida, Masako Kato
    INORGANIC CHEMISTRY 54 (18) 8878 - 8880 0020-1669 2015/09 [Refereed][Not invited]
     
    A new luminescent cyclometalated platinum(II) complex containing a carboxyl group, trans-[Pt(pcppy)(pic)] [1-COOH; Hpcppy = 2-(p-carboxyphenyl)pyridine and Hpic = picolinic acid] has been synthesized and characterized. The luminescence behavior of 1-COOH in the solid and solution states is completely different despite the similarity of the luminescence in both states for the nonsubstituted complex, [Pt(ppy)(pic)] (1-H; Hppy = 2-phenylpyridine). Interestingly, 1-COOH exhibits concentration-dependent absorption and emission behavior based on its aggregation in a basic aqueous solution despite the absence of amphiphilic character.
  • Fumi Kitamura, Kana Sawaguchi, Asami Mori, Shoji Takagi, Takayoshi Suzuki, Atsushi Kobayashi, Masako Kato, Kiyohiko Nakajima
    INORGANIC CHEMISTRY 54 (17) 8436 - 8448 0020-1669 2015/09 [Refereed][Not invited]
     
    We prepared hydrazone palladium(II) complexes of [PdCl2(HLn)] and [PdCl(L-n)] (n = 1-3) by the reaction of [PdCl2(cod)] or [PdCl2(PhCN)(2)] and the hydrazone ligands of HLn {N'-(pyridin-2-ylmethylene)picolinohydrazide (HL1), N'-[1-(pyridin-2-yl)ethylidene]picolinohydrazide (HL2), and N'-[(6-methylpyridin-2-yOmethylene]picolinohydrazide (HL3)}. The structures of the complexes were determined by X-ray analysis. The hydrazone ligands had kappa N(pyl), kappa N(imine) and kappa N(amidate) kappa N(py2) bidentate coordination modes in [PdCl2(HLn] (1, n = 1; 2, n = 2) and in [PdCl2(HL3)] (3), respectively. In contrast, tridentate coordination modes of kappa N(pyl)), kappa N(imine), kappa N(py2) and kappa N(py1), kappa N(amidate), kappa N(py2) were observed in [PdCl(L-n)] (4, n = 1; 5, n = 2) and in [PdCl(L-n)] (6, n = 1; 7, n = 2; 8, n = 3). Thermal conversion of complexes 1-3 to complexes 6-8 proceeded in acetonitrile. Complexes 4 and 5 were obtained from complexes 1 and 2, respectively, in a basic acetonitrile solution under dark conditions. Complex 4 reverted immediately to complex 1 in an acidic acetonitrile solution that included hydrochloric acid. However, under room light, in the basic acetonitrile solution that included trimethylamine, complex 4 converted photochemically to complex 6. The thermochromic or vapochromic structure conversion of these complexes also occurred in the solid state. On heating at 180 degrees C, the color of the crystals of complexes 1, 2, and 3 changed from yellow to orange in the solid state. H-1 NMR and/or UV vis absorption spectroscopy confirmed that the orange complexes 6-8 were produced. The reddish-orange crystals of complexes 4 and 5 were exposed to hydrogen chloride vapor to yield the yellow products of complexes 1 and 2, respectively.
  • Hiroki Ohara, Atsushi Kobayashi, Masako Kato
    COMPTES RENDUS CHIMIE 18 (7) 766 - 775 1631-0748 2015/07 [Refereed][Not invited]
     
    A series of mononuclear Cu(I)-halide complexes, [CuX(PPh3)(2)(L)] (X= CI-, Br-, I-; PPh3 = triphenylphosphine; L = pyridine (py), isoquinoline (iq), 1,6-naphthyridine (nap)), were synthesized. The emission color of [CuX(PPh3)2(L)] varies from blue to red by changing the L ligands and the halide ions, and all the complexes exhibit high emission quantum yields (0.16-0.99) in the crystals. The emission studies revealed that the emissive states of [CuX(PPh3)(2)(L)] differ depending on the L ligand. Complexes [CuX(PPh3)(2)(py)] and [CuX(PPh3)2(nap)] mainly emit from the singlet metal-to-ligand charge transfer mixed with the halide-to-ligand charge transfer ((1)(M + X)LCT) state at room temperature. In contrast, emissions from [CuX(PPh3)(2)(iq)] at room temperature originate from both (3)(M + X)LCT and (3)pi pi* states. These results indicate that N-heterodomatic ligands play an important role in the emission properties of mononuclear Cu(I)-halide complexes. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
  • Yasuchika Hasegawa, Nao Sato, Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Atsushi Kobayashi, Masako Kato, Tomohiro Seki, Hajime Ito, Koji Fushimi
    JOURNAL OF PHYSICAL CHEMISTRY A 119 (20) 4825 - 4833 1089-5639 2015/05 [Refereed][Not invited]
     
    Enhanced luminescence of a lanthanide complex with dynamic polarization of the excited state and molecular motion is introduced. The luminescent lanthanide complex is composed of one Eu(hfa)(3) (hfa, hexafluoroacetylacetonate) and two phosphine oxide ligands with ruthenocenyl units Rc, [Eu(hfa)(3)(RcPO)(2)] (RcPO = diphenylphosphorylruthenocene). The ruthenocenyl units in the phosphine oxide ligands play an important role of switching for dynamic molecular polarization and motion in liquid media. The oxidation states of the ruthenocenyl unit (Rc(1+)/Rc(1+)) are controlled by potentiostatic polarization. Eu(III) complexes attached with bidentate phosphine oxide ligands containing ruthenocenyl units, [Eu(hfa)(3)(RcBPO)] (RcBPO = 1,1'-bis(diphenylphosphoryl)ruthenocene), and with bidentate phosphine oxide ligands, [Eu(hfa)(3)(BIPHEPO)] (BIPHEPO =1,1'-biphenyl-2,2'-diylbis(diphenylphosphine oxide), were also prepared as references. The coordination structures and electrochemical properties were analyzed using single crystal X-ray analysis, cyclic voltammetry, and absorption spectroscopy measurements. The luminescence properties were estimated using an optoelectrochemical cell. Under potentiostatic polarization, a significant enhancement of luminescence was successfully observed for [Eu(hfa)(3)(RcPO)(2)], while no spectral change was observed for [Eu(hfa)(3)(RcBPO)]. In this study, the remarkable enhanced luminescence phenomena of Eu(III) complex based on the dynamic molecular motion under potentiostatic polarization have been performed.
  • Atsushi Kobayashi, Yui Suzuki, Tadashi Ohba, Tomohiro Ogawa, Takeshi Matsumoto, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 54 (6) 2522 - 2535 0020-1669 2015/03 [Refereed][Not invited]
     
    A series of flexible porous coordination polymers (PCPs) RE-Co, composed of a Co(III)-metalloligand [Co(dcbpy)(3)](3-) (Co; H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and lanthanide cations (RE3+ = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Er3+), was systematically synthesized. X-ray crystallographic analysis revealed that the six carboxylates at the top of each coordination octahedron of Co(III)-metalloligand were commonly bound to RE3+ cations to form a rock-salt-type porous coordination framework. When RE-Co contains a smaller and heavier RE3+ cation than Nd3+, the RE-Co crystallized in the cubic Fm-3m space group, whereas the other three RE-Co with larger RE3+ crystallized in the lower symmetrical orthorhombic Fddd space group, owing to the asymmetric 10-coordinated bicapped square antiprism structure of the larger RE3+ cation. Powder X-ray diffraction and vapor-adsorption isotherm measurements revealed that all synthesized RE-Co PCPs show reversible amorphous-crystalline transitions, triggered by water-vapor-adsorption/desorption. This transition behavior strongly depends on the kind of RE3+; the transition of orthorhombic RE-Co was hardly observed under exposure to CH3OH vapor, but the RE-Co with smaller cations such as Gd3+ showed the transition under exposure to CH3OH vapors. Further tuning of vapor-adsorption property was examined by doping of Ru(II)-metalloligands, [Ru(dcbpy)(3)](4-), [Ru(dcbpy)(2)Cl-2](4-), [Ru(dcbpy)(tpy)Cl](-), and [Ru(dcbpy)(dctpy)](3-) (abbreviated as RuA, RuB, RuC, and RuD, respectively; tpy = 2,2':6',2?-terpyridine, H2dctpy = 4,4"-dicarboxy-2,2':6',2"-terpyridine), into the Co(III)-metalloligand site of Gd-Co to form the Ru(II)-doped PCP RuX@Gd-Co (X = A, B, C, or D). Three Ru(II)-metalloligands, RuA, RuB, and RuD dopants, were found to be uniformly incorporated into the Gd-Co framework by replacing the original Co(III)-metalloligand, whereas the doping of RuC failed probably because of the less number of coordination sites. In addition, we found that the RuA doping into the Gd-Co PCP had a large effect on vapor-adsorption due to the electrostatic interaction originating from the negatively charged RuA sites in the framework and the charge-compensating Li+ cations in the porous channel.
  • Tomohiro Ogawa, Masaki Yoshida, Hiroki Ohara, Atsushi Kobayashia, Masako Kato
    CHEMICAL COMMUNICATIONS 51 (69) 13377 - 13380 1359-7345 2015 [Refereed][Not invited]
     
    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.
  • Masanori Wakizaka, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Ho-Chol Chang
    DALTON TRANSACTIONS 44 (32) 14304 - 14314 1477-9226 2015 [Refereed][Not invited]
     
    The redox-active metalloligand (RML) (Et3NH)(3)[Cr-III(F(4)Cat)(3)] (F(4)Cat = perfluorocatecholato) (1) was synthesized and its interactions with guest metal ions Li+, Mn2+, Fe2+, Co2+, Cu2+, and Zn2+ were examined. Cyclic voltammetry measurements and spectroelectrochemical studies revealed that complex 1 shows three-step ligand-centred one-electron oxidation to consecutively generate [Cr-III(F(4)Cat)(2)(F(4)SQ)](2-) (F(4)SQ = perfluorosemiquinonato), [Cr-III(F(4)Cat)(F(4)SQ)(2)](-), and [Cr-III(F(4)SQ)(3)] at -0.12, 0.23, and 0.53 V vs. Ag/Ag+ in dichloromethane, or at -0.21, 0.08, and 0.50 V in acetonitrile (MeCN), respectively. Titration experiments in MeCN revealed that treatment of 1 with Cu2+ leads to the formation of [Cr-III(F(4)Cat)(2)(F(4)SQ)](2-) and Cu+ via a redox reaction. However, when 1 was treated with Li+, Mn2+, Fe2+, Co2+, and Zn2+, further titration experiments revealed that these metal ions coordinated via the lone pairs on the coordinating oxygen atoms of the F(4)Cat(2-) moieties in a one-to-one ratio, and binding constants of 3.7 (+/- 0.3) x 10(4) (Li+), 1.5 (+/- 0.2) x 10(5) (Mn2+), 2.2 (+/- 0.4) x 10(5) (Fe2+), 1.9 (+/- 0.2) x 10(5) (Co2+), and 3.8 (+/- 0.4) x 10(5) M-1 (Zn2+) were established. Moreover, the oxidation potentials of 1 were positively shifted by 0.08-0.33 V upon addition of guest metal ions. Spectroelectrochemical studies of 1 in the presence of guest metal ions suggested that ligand-centred one- and two-electron oxidation of the RML occurred for Li+, Mn2+, Co2+, and Zn2+, respectively, while guest metal-centred one-electron oxidation was observed for Fe2+. Considering all the aforementioned results, this study demonstrated for the first time the ability of [Cr-III(F(4)Cat)(3)](3-) to act as a RML in solution.
  • Takeshi Matsumoto, Hirokazu Yano, Masanori Wakizaka, Atsushi Kobayashi, Masako Kato, Ho-Chol Chang
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 88 (1) 74 - 83 0009-2673 2015/01 [Refereed][Not invited]
     
    The reactions of [Mo-2(II)(OAc)(4)] (OAc-: acetato) with catecholato derivatives (R-Cat(2-)), possessing electron-donating t-Bu groups (3,6-DTBCat(2-)) or electron-withdrawing Br groups (Br(4)Cat(2-)), results in the formation of a mononuclear complex [Na(THF)(6)][Mo-V(3,6-DTBCat)(3)] (1) and a dinuclear complex either [Na-6(Br(4)SQ)(2)][Mo-2(IV)(mu-O)(2)-(Br(4)Cat)(4)] or [Na-6(Br(4)Cat)(2)][Mo-2(V)(mu-O)(2)(Br(4)Cat)(4)] (3). Complex 3 has a [Mo(mu-O)(2)Mo] core as part of a dimer of [O=Mo-m(Br(4)Cat)(2)](n-) (m = IV or V, n= 2 or 1) moieties assembled in a head-to-tail arrangement, which has been structurally characterized as the a bis-mu-oxo molybdenum dinuclear complex containing catecholato ligands. The bond distance between the Mo atoms (2.4286(17) angstrom) strongly suggests that a Mo-IV=Mo-IV or Mo-V-Mo-V bonding character exists in 3. Differences in the substituent groups on the catecholato ligand affect not only the product formed but also the reactivity of both complexes. Complex 3 shows O-atom abstraction reactivity with dimethyl sulfoxide (DMSO) and forms dimethyl sulfide (DMS). These results support a high oxophilicity of the Mo center in 3.
  • Tomohiro Ogawa, Masaki Yoshida, Hiroki Ohara, Atsushi Kobayashia, Masako Kato
    CHEMICAL COMMUNICATIONS 51 (69) 13377 - 13380 1359-7345 2015 [Refereed][Not invited]
     
    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.
  • Yurika Yamashita, Tomoya Tateishi, Kana Sawaguchi, Atsushi Kobayashi, Masako Kato, Kiyohiko Nakajima
    CHEMISTRY LETTERS 43 (12) 1912 - 1914 0366-7022 2014/12 [Refereed][Not invited]
     
    Pt(II) complexes containing tridentate hydrazone ligands were prepared. Reversible protonation and deprotonation of the hydrazone complexes occurred in solution and in the solid state. On grinding and heating the yellow-colored crystals of the protonated complex [PtCl(HL)]Cl, the deprotonated red-colored product, [PtCl(L)], was produced, and HCl vapor was released. The deprotonated complex reverted to the yellow-colored protonated complex on exposure of the red-colored crystals to HCl vapor. Both [PtCl(HL)]Cl and [PtCl(L)] exhibited different luminescence colors in acetonitrile solution.
  • Atsushi Kobayashi, Masako Kato
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2014 (27) 4469 - 4483 1434-1948 2014/09 [Refereed][Not invited]
     
    Vapochromic materials that show reversible color change driven by vapor adsorption/desorption have drawn significant attention because of their potential applications in chemical sensors and chemical-switching modules. Among the vapochromic coordination complexes reported so far, a series of square-planar Pt-II complexes has been studied and represents one of the most promising systems for practical chemical sensors. For such systems, the color of the complexes strongly depends not only on the ligand-field splitting, but also on the intermolecular distance between the Pt-II ions. This microreview presents recent results of vapochromic complexes centered on one-dimensionally stacked Pt-II systems from the viewpoint of the origin of their vapochromic behavior. The design of vapochromic materials has been facilitated because several useful chromophores, including metallophilic interaction between Pt-II ions, have been developed. However, it is still challenging to realize a specifically sensitive and selective response to targeted vapors. This review focuses on strategies to achieve assembled Pt-II complexes with selective vapochromic responses.
  • Hiroki Ohara, Atsushi Kobayashi, Masako Kato
    CHEMISTRY LETTERS 43 (8) 1324 - 1326 0366-7022 2014/08 [Refereed][Not invited]
     
    Highly luminescent mononuclear copper(I) iodide complexes [CuI(PPh3)(2)(L)] have been synthesized by simple manual grinding of copper(I) iodide, PPh3, and N-heteroaromatic ligands (L = isoquinoline, 1,6-naphthyridine, and pyridine). They exhibit different colors of luminescence depending on L affording very high quantum yields (0.63-0.99).
  • Hirotaka Honda, Takeshi Matsumoto, Ryo Tamura, Katsuhiko Kanaizuka, Atsushi Kobayashi, Masako Kato, Masa-aki Haga, Ho-Chol Chang
    CHEMISTRY LETTERS 43 (8) 1189 - 1191 0366-7022 2014/08 [Refereed][Not invited]
     
    The reaction of tetraethyl [2,3-dihydroxy-1,4-phenylenebis-(methylene)]bisphosphonate (Et4LH2) with [PtCl2(DTBbPY)] (DTBbpy: 4,4'-di-tert-butyl-2,2'-bipyridine) afforded [Pt(Me4L)-(DTBbpY)] (1), [Pt(Bn4L-)(DTBbPY)] (2), Na-2[Pt(Me2L)-(DTBbpy)] (3), and [Pt(H4L)(DTBbpy)] (4) with tetramethyl-, tetrabenzyl-, half-protected, and fully-deprotected groups under different reaction conditions. The introduction of phosphonatomethyl groups at the 3,6-position of a redox-active catecholato unit led to slight shifts in charge-transfer bands and catecholato-centered redox processes in solution. The presence of deprotonated anchors in 3 resulted in the immobilization of the complex onto an indium-doped tin oxide electrode, demonstrating a well-defined redox response from the tethered complex.
  • Atsushi Kobayashi, Akira Sugiyama, Tadashi Ohba, Yui Suzuki, Ho-Chol Chang, Masako Kato
    CHEMISTRY LETTERS 43 (7) 1070 - 1072 0366-7022 2014/07 [Refereed][Not invited]
     
    A new porous coordination polymer (PCP), formulated as {[La-2(III)(mu(3)-OH)(CH3COO)(2)(H2O)][Cu-I(dmdcbpy)(2)]center dot 9H(2)O} (La2Cu center dot 9H(2)O; H(2)dmdcbpy: 6,6'-dimethyl-5,5'-dicarboxy-2,2'bipyridine), was synthesized and characterized by X-ray diffraction and vapor-adsorption isotherms. The porous framework of La2Cu consists of a 3-D coordination network of the Cu(I)-metalloligand and the tetranuclear La-4 cluster {La-4(mu(3)-OH)(2)(CH3COO)(4)(H2O)(2)}. La2Cu exhibits reversible guest adsorption desorption for various vapors, with reversible structural transformations.
  • Atsushi Kobayashi, Daisuke Yamamoto, Hiroyuki Horiki, Kana Sawaguchi, Takeshi Matsumoto, Kiyohiko Nakajima, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 53 (5) 2573 - 2581 0020-1669 2014/03 [Refereed][Not invited]
     
    Photoreactivities of Ni(II)- and Pt(II)- hydrazone complexes, [NiCI(L)] (Ni1) and [PtCl(L)] (Pt1), respectively [HL = 2-(diphenylphosphino)benzaldehyde-2-pyridylhydrazone], were investigated in detail via UV-vis absorption, H-1 nuclear magnetic resonance (NMR) spectroscopy, and electrospray ionization time-of-flight (ESI-TOF) mass spectrometry; the two photoproducts obtained from the photoreaction of Pt1 were also successfully identified via X-ray analysis. The absorption bands of the Ni1 and Pt1 complexes were very similar, centered around 530 nm, and were assigned as an intraligand charge transfer transition of the hydrazone moiety. The absorption spectrum of Pt1 in a CH3CN solution changed drastically upon photoirradiation (lambda = 530 nm), whereas no change was observed for Ni1. H-1 NMR and ESI-TOF mass spectra under various conditions suggested that the photoexcited Pt1* reacts with dissolved dioxygen to form a reactive intermediate, and the ensuing dark reactions afforded two different products without any decomposition. In contrast to the simple photo-oxidation of HL to form a phosphine oxide HL(P=O), the X-ray crystallographic analyses of the photoproducts clearly indicate the formation of a mononuclear Pt complex with the oxygenated hydrazone ligand (Pt10) and a dinuclear Pt complex with the oxygenated and dimerized hydrazone ligand (Pt2). The photosensitized reaction in the presence of an O-1(2)-generating photosensitizer, methylene blue (MB), also produced Pt1O and Pt2, indicating that the reaction between O-1(2) and ground-state Pt1 is the important step. In a highly viscous dimethyl sulfoxide solution, Pt1 was slowly, but quantitatively, converted to the mononuclear form, Pt1O, without the formation of the dinuclear product, Pt2, upon photoirradiation (and in the reaction photosensitized by MB), suggesting that this photoreaction of Pt1 involves at least one diffusion-controlled reaction. On the other hand, the same complexes Pt1O and Pt2 were also produced in the degassed solution, probably because of the reaction of the photoexcited Pt1* with the biradical character and H2O.
  • Atsushi Kobayashi, Tadashi Ohba, Erika Saitoh, Yui Suzuki, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 53 (6) 2910 - 2921 0020-1669 2014/03 [Refereed][Not invited]
     
    Coordination polymerization reactions between ruthenium(II) metalloligands [Ru(n,n'-dcbpy)](4-) ([nRu]; n = 4, 5; n,n'-dcbpy = n,n'-dicarboxy-2,2'-bipyridine) and several divalent metal salts in basic aqueous solutions afforded porous luminescent complexes formulated as [Mg(H2O)(6)]{[Mg(H2O)(3)][4Ru]center dot 4H(2)O} (Mg-2[4Ru]center dot 13H(2)O), [Mg-2(H2O)(9)][5Ru]center dot 10H(2)O (Mg-2[5Ru]center dot 19H(2)O), {[Sr-4(H2O)(9)][4Ru](2)center dot 9H(2)O} (Sr-2[4Ru]center dot 9H(2)O)(2), {[Sr-2(H2O)(8)][5Ru]center dot 6H(2)O} (Sr-2[5Ru]center dot 14H(2)O), and {[Cd-2(H2O)(2)][5Ru]center dot 10H(2)O} (Cd-2[5Ru]center dot 12H(2)O). Single-crystal X-ray structural analyses revealed that the divalent metal ions were commonly coordinated by the carboxyl groups of the [nRu] metalloligand, forming porous frameworks with a void fraction varying from 11.4% Mg-2[4Ru]center dot 13H(2)O to 43.9% Cd-2[5Ru]center dot 12H(2)O. M-2[4Ru]center dot nH(2)O showed a reversible structural transition accompanied by water and methanol vapor adsorption/desorption, while the porous structures of M-2[5Ru]center dot nH(2)O were irreversibly collapsed by the removal of crystal water. The triplet metal-to-ligand charge-transfer emission energies of M-2[4Ru]center dot nH(2)O were lower than those of [4Ru] in aqueous solution, whereas those of M-2[5Ru]center dot nH(2)O were close to those of [5Ru] in aqueous solution. These results suggested that the position of the coordination site in the metalloligand played an important role not only on the structure of the porous framework but also on the structural flexibility involving the guest adsorption/desorption properties.
  • Hiroki Ohara, Atsushi Kobayashi, Masako Kato
    DALTON TRANSACTIONS 43 (46) 17317 - 17323 1477-9226 2014 [Refereed][Not invited]
     
    Simple mononuclear Cu(I)-halide complexes, [CuX(PPh3)(2)(4-Mepy)] (X = Cl-, Br-, I-; PPh3 = triphenylphosphine; 4-Mepy = 4-methylpyridine), were prepared. They exhibit blue light emission, with extremely high photoluminescence quantum yields approaching 100% in the crystals. Emission lifetime analyses and density functional theory calculations revealed that the bright blue light emission at room temperature is mainly delayed fluorescence originating from the singlet metal-to-ligand charge transfer (MLCT) state combined with the halide-to-ligand charge transfer (XLCT) state, ((1)(M + X)LCT), while that at 77 K is phosphorescence from the (3)(M + X) LCT transition state, due to the small singlet-triplet energy differences (Delta E = 940-1170 cm(-1)). The ternary ligand systems consisting of halide, bulky phosphine, and N-heteroaromatic ligands constitute inexpensive pure-blue-light-emitting materials, which can be fabricated by facile procedures such as simple manual grinding.
  • Asami Mori, Takayoshi Suzuki, Yukinari Sunatsuki, Atsushi Kobayashi, Masako Kato, Masaaki Kojima, Kiyohiko Nakajima
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2014 (1) 186 - 197 1434-1948 2014/01 [Refereed][Not invited]
     
    The reactions of quinoline-2-carbaldehyde (pyridine-2-carbonyl)hydrazone (HL) and [RuCl2(PPh3)(3)] in various solvents at different temperatures gave the three geometrical isomers trans(Cl,Cl)-, cis(Cl,Cl),trans(P,N)-, and trans(P,P)-[RuCl2(PPh3)(2){HL-O(amide),N(imine)}] (1, 2, and 3, respectively) as well as a linkage isomer trans(P,P)-[RuCl2(PPh3)(2){HL-N(imine),N(quin)}] (4). The molecular and crystal structures of 1-4, together with both E and Z configurational isomers (with respect to the C=N double bond) of the free ligand HL, were determined by X-ray analysis. The ligand HL adopted a Z form and acted as a O(amide),N(imine) bidentate ligand in 1-3, whereas it was an E isomer with a N(imine),N(quin) coordination mode in 4. The gradual thermal conversions of 1 to 2 and of 2 to 3 were observed in dichloromethane and ethanol, respectively, but an interconversion between 3 and 4 was not detected. In dichloromethane, all complexes have a reversible Ru-III/II redox couple in the range 110-412 mV (vs. Ag/Ag+), and the redox potential was largely dependent on the coordination mode of HL and on the mutual configuration of the two PPh3 ligands. Such a potential shift can be interpreted as a combination of Cl-/amide O -donor and PPh3/quinoline N -acceptor orbital contributions to the Ru-II d orbitals [highest occupied molecular orbitals (HOMOs)]. Complexes 3 and 4 in acetonitrile showed a gradual spectral change, probably because of the substitution of the Cl- ligand by the acetonitrile solvent. In addition, 2-4 showed solvatochromic behavior even in noncoordinating solvents that resulted from a blueshift of the metal-to-ligand charge-transfer (MLCT) transition band in polar solvents. These electrochemical and spectroscopic properties are also supported by DFT and time-dependent DFT (TD-DFT) calculations.
  • Hiroki Ohara, Atsushi Kobayashi, Masako Kato
    DALTON TRANSACTIONS 43 (46) 17317 - 17323 1477-9226 2014 [Refereed][Not invited]
     
    Simple mononuclear Cu(I)-halide complexes, [CuX(PPh3)(2)(4-Mepy)] (X = Cl-, Br-, I-; PPh3 = triphenylphosphine; 4-Mepy = 4-methylpyridine), were prepared. They exhibit blue light emission, with extremely high photoluminescence quantum yields approaching 100% in the crystals. Emission lifetime analyses and density functional theory calculations revealed that the bright blue light emission at room temperature is mainly delayed fluorescence originating from the singlet metal-to-ligand charge transfer (MLCT) state combined with the halide-to-ligand charge transfer (XLCT) state, ((1)(M + X)LCT), while that at 77 K is phosphorescence from the (3)(M + X) LCT transition state, due to the small singlet-triplet energy differences (Delta E = 940-1170 cm(-1)). The ternary ligand systems consisting of halide, bulky phosphine, and N-heteroaromatic ligands constitute inexpensive pure-blue-light-emitting materials, which can be fabricated by facile procedures such as simple manual grinding.
  • Tadashi Ohba, Atsushi Kobayashi, Ho-Chol Chang, Takahiko Kouyama, Tatsuhisa Kato, Masako Kato
    DALTON TRANSACTIONS 43 (20) 7514 - 7521 1477-9226 2014 [Refereed][Not invited]
     
    A heterodinuclear complex, syn-[PtCu(mu-pyt)(2)(bpy)(2)](2+) (syn-[PtCu]; Hpyt = pyridine-2-thiol, bpy = 2,2 '-bipyridine), was synthesized by stepwise complexation. Three different crystal structures of the hexafluorophosphate salts with solvent molecules as guests at the axial sites of the Cu(II) ions, i.e. syn-[PtCu-G] (G = acetonitrile, acetone, and methanol), were determined by X-ray analyses. In the solid-state, these complexes adopt dimer-of-dimer motifs characteristic of the syn isomers of dinuclear complexes with two pyt bridging ligands arranged in a head-to-head configuration. These dinuclear complexes have a short Pt. Cu distance (2.75-2.81 angstrom) and slightly different intermolecular Pt...Pt distances (3.43-3.51 angstrom), which affect the colour of the solid complexes. All the syn-[PtCu-G] systems absorbed/desorbed vapour molecules; however, they exhibit different chromic changes because of the unique structural hysteresis of the desorbed form, i. e. syn-[PtCu], according to powder X-ray diffraction measurements. In addition, guest exchange occurred in the syn-[PtM-G] complexes upon exposure to the vapour of different solvents.
  • Tomohiro Ogawa, Misaki Sakamoto, Hirotaka Honda, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Ho-Chol Chang
    Dalton Transactions 42 (45) 15995 - 16005 1477-9226 2013/12/07 [Refereed][Not invited]
     
    The introduction of a Au(iii) ion into a mesogenic core, [M(Bdt)(Cnbpy)]+ (Bdt = 1,2-benzenedithiolato and Cnbpy = 4,4′-di-alkyl-2,2′-bipyridine (n = 13 (4,4′-di-tridecyl-2, 2′-bipyridine (C13bpy)) and 8,10 (4,4′-di-(3-octyltridecyl)-2, 2′-bipyridine (C8,10bpy)))), leads to the formation of ionic molecular assemblies in crystalline and mesophases. Successive syntheses of precursor complexes, [AuCl2(Cnbpy)]PF6 (n = 13 (1) and 8,10 (2)), followed by the target complexes, [Au(Bdt)(Cnbpy)]PF6 (n = 13 (3) and 8,10 (4)), were achieved. The crystallographic analysis of 3 revealed that the central cationic cores form a characteristic one-dimensional columnar structure, which is an essential property for the formation of columnar structures in the liquid crystalline phase. The central cores of the [Au(Bdt)(C13bpy)]+ cations in 3 stack alternatively so as to cancel out their dipole moments and the counteranions lie between the cationic columns. Furthermore, the introduction of the branched alkyl tails in 4 induces the formation of a rectangular columnar liquid crystalline phase (Colr) with C2/m symmetry, and it melts to an isotropic liquid at 69 °C. The Colr phase of 4 is partially similar in its liquid crystalline structure to the neutral [Pt(Bdt)(C8,10bpy)] liquid crystal in a hexagonal columnar phase reported previously, while complex 4 shows a lower clearing point than that of the Pt analogue. Based on these results, the present study demonstrates the designability of the liquid crystalline structures of the [M(Bdt)(C8,10bpy)] skeleton together with their assembled structures and physico-chemical properties. © 2013 The Royal Society of Chemistry.
  • Yasuchika Hasegawa, Tomoki Ohkubo, Takayuki Nakanishi, Atsushi Kobayashi, Masako Kato, Tomohiro Seki, Hajime Ito, Koji Fushimi
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2013 (34) 5911 - 5918 1434-1948 2013/12 [Refereed][Not invited]
     
    The effect of ligand polarization on the formation of strongly luminescent lanthanide complexes with asymmetric structures is described for the first time. The lanthanide complexes are composed of Eu-III ions, three hexafluoroacetylacetonate (hfa) ligands, and two monodentate phosphine oxide ligands, namely, triphenylphosphine oxide (TPPO), p-tolyldiphenylphosphine oxide (TPPO-Me), tri-p-tolylphosphine oxide (TPPO-3Me) or o-phenoxyphenyldiphenylphosphine oxide (TPPO-OPh). The luminescence properties of the Eu-III complexes are characterized by their emission quantum yields, emission lifetimes, and their radiative (k(r)) and nonradiative (k(nr)) rate constants. The Eu-III complex with TPPO-OPh ligands offers a markedly high emission quantum yield (72% in [D-6]acetone, 85% in the solid state) owing to enhancement of the electric dipole transition and suppression of vibrational relaxation, which are directly related to k(r) and k(nr). The coordination geometries of the Eu-III complexes are categorized by shape-measure calculations. The Eu-III complexes exhibit characteristic square-antiprismatic or trigonal-dodecahedral structures, depending on the ligand polarization. Strongly luminescent Eu(hfa)(3)(TPPO-OPh)(2) has an asymmetric dodecahedron structure. The formation of distorted dodecahedral structures with low vibrational frequencies for the enhancement of luminescence is elucidated in terms of the ligand polarization of the monodentate phosphine oxide ligands in the Eu-III complexes.
  • Atsushi Kobayashi, Kahori Komatsu, Hiroki Ohara, Waka Kamada, Yuko Chishina, Kiyoshi Tsuge, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 52 (22) 13188 - 13198 0020-1669 2013/11 [Refereed][Not invited]
     
    Halide-bridged rhombic dicopper(I) complexes, [Cu-2(mu-X)(2)(DMSO)(2)(PPh3)(2)] (X = I-, Br-; DMSO = dimethyl sulfoxide; PPh3 = triphenylphosphine), were synthesized, the iodide complex of which exhibited interesting photochromic luminescence driven by photoirradiation and by exposure to DMSO vapor in the solid state. Single-crystal Xray diffraction measurements revealed that the iodo and bromo complexes (abbreviated Cu2I2-[O,O] and Cu2Br2-[O,O]) were isomorphous, and that the two DMSO ligands were coordinated to the Cu(I) ion via the O atom in both complexes. Both complexes exhibited bright blue phosphorescence at room temperature (lambda(em) = 435 nm, Phi(em) = 0.19 and 0.14 for Cu2I2[O,O] and Cu2Br2-[O,O], respectively) with a relatively long emission lifetime (tau(em) similar to 200 mu s at 77 K) derived from the mixed halide-to-ligand and metal-to-ligand charge transfer ((XLCT)-X-3 and (MLCT)-M-3) excited state. Under UV irradiation, the blue phosphorescence of Cu2Br2-[O,O] disappeared uneventfully and no new emission band appeared, whereas the blue phosphorescence of Cu2I2-[O,O] rapidly disappeared with simultaneous appearance of a new green emission band (lambda(em) = 500 nm). On further irradiation, the green emission of the iodide complex gradually changed to bright yellowish-green (lambda(em) = 540 nm); however, this change could be completely suppressed by lowering the temperature to 263 K or in the presence of saturated DMSO vapor. The initial blue phosphorescence of Cu2I2-[O,O] was recovered by exposure to DMSO vapor at 90 degrees C for a few hours. IR spectroscopy and theoretical calculations suggest that the DMSO ligand underwent linkage isomerization from O-coordination to S-coordination, and both the occurrence of linkage isomerization and the removal of DMSO result in contraction of the rhombic Cu2O4-O-2 core to make the Cu.-Cu interaction more effective. In the contracted core, the triplet cluster-centered ((CC)-C-3) emissive state is easily generated by thermal excitation of the (XLCT)-X-3 and (MLCT)-M-3 mixed transition state, resulting in the green to yellowish-green emission. In contrast, the Cu"Cu distance in Cu2Br2-[O,O] is considerably longer than that of Cu2I2[O,O], which destabilizes the (CC)-C-3 emissive state, resulting in the nonemissive character.
  • Toshifumi Iimori, Yoshikiyo Hatakeyama, Keiko Nishikawa, Masako Kato, Nobuhiro Ohta
    CHEMICAL PHYSICS LETTERS 586 100 - 103 0009-2614 2013/10 [Refereed][Not invited]
     
    Photoluminescence (PL) is observed for gold nanoparticles prepared by using sputter deposition technique and stably dispersed in a room-temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate. PL spectrum in the visible region depends on the excitation wavelength; the spectrum is shifted to longer wavelengths, as the excitation wavelength becomes longer, which probably comes from the size distribution of nanoparticles. Decay profiles as well as quantum yields of PL are measured at different excitation wavelengths. PL intensity shows a multiexponential decay, and the average lifetime, which depends on the excitation wavelength, is shorter than 3 ns. (C) 2013 Elsevier B.V. All rights reserved.
  • Takeshi Matsumoto, Ho-Chol Chang, Masanori Wakizaka, Sho Ueno, Atsushi Kobayashi, Akira Nakayama, Tetsuya Taketsugu, Masako Kato
    Journal of the American Chemical Society 135 (23) 8646 - 8654 0002-7863 2013/06/12 [Refereed][Not invited]
     
    The combination of o-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris(o-phenylenediamine) iron(II) complex, [FeII(opda)3](ClO4)2 (1), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV-vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H+/e- donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H+/e- pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H2 production/storage materials. © 2013 American Chemical Society.
  • Hirotaka Honda, Takeshi Matsumoto, Misaki Sakamoto, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 52 (8) 4324 - 4334 0020-1669 2013/04 [Refereed][Not invited]
     
    The presence of lone pairs on the Pt and S atoms of [Pt(Bdt)(DTBbpy)] (1) (Bdt = 1,2-benzenedithiolato and DTBbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) and [Pt (Bdt) (C13bpy)] (2) (C13bpy = 4,4'-ditridecyl-2,2'-bipyridine) led to selective dative bond formation with Cd(II). Complexes 1 and 2 show no binding interaction with Zn(II), while they bind selectively with Cd(II) to give a twisted trinuclear complex, [Cd{Pt(Bdt)(DTBbpy)}(2)(ClO4)(H2O)](ClO4) (3), and a shuttlecock-shaped tetranuclear complex, [Cd{Pt(Bdt)(C13bpy)}(3)(H2O)](ClO4)(2)center dot CH2Cl2 (4), respectively, depending upon the alkyl groups substituted on the 2,2'-bipyridine. The two platinum moieties in 3 are connected to the seven-coordinated Cd atom through Pt -> Cd (2.7331(7) and 2.7936(7) angstrom) and S -> Cd (2.690(3), 2.940(3), and 3.067(3) angstrom) dative bonds, while the three moieties in 4 are connected to the tetrahedral Cd atom only by S -> Cd (2.552(4) angstrom) dative bonds. These structural variations found in 3 and 4 are caused not only by steric hindrance of the t-Bu groups but also by the microsegregation effect derived from the tridecyl chains. The three platinum moieties in 4 align so as to form a parallel orientation of their dipole moments, in contrast to the twisted arrangement found in 3. The dative bonds formed in 3 and 4 are commonly stable in the solid state and in less coordinative solvents such as dichloromethane, while dissociation behavior of platinum moieties with Cd(II) was observed in more coordinative THF. UV-vis and NMR spectroscopy unsealed the characteristic association/dissociation properties depending on the coordination abilities of solvents. Finally, the present study revealed that the formation of dative bonds between the platinum moieties with Cd(II) plays important roles not only in stabilizing the ground states, which leads to blue shifts in both absorption and emission energies, but also in electronic interactions between the moieties, which are revealed by electrochemical studies.
  • Ohba T, Kobayashi A, Chang H.-C, Kato M
    Dalton. Trans. 42 (15) 5490 - 5499 2013 [Refereed][Not invited]
  • Kohei Miyata, Yuji Konno, Takayuki Nakanishi, Atsushi Kobayashi, Masako Kato, Koji Fushimi, Yasuchika Hasegawa
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 52 (25) 6413 - 6416 1433-7851 2013 [Refereed][Not invited]
  • Yuta Kajitani, Kiyoshi Tsuge, Yoichi Sasaki, Masako Kato
    CHEMISTRY-A EUROPEAN JOURNAL 18 (36) 11196 - 11200 0947-6539 2012/09 [Refereed][Not invited]
  • Atsushi Kobayashi, Yuki Fukuzawa, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 51 (14) 7508 - 7519 0020-1669 2012/07 [Refereed][Not invited]
     
    We synthesized a novel Pt(II)-diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)(2)(H(2)dcbpy)] (1; H(2)dcbpy =4,4'-dicarboxy-2,2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl2(H(2)dcbpy)] and KSCN in aqueous solution at 0 degrees C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)(2)(H(2)dcbpy)] (1SS center dot H2O), as a nonluminescent orange solid. Interestingly, 1SS center dot H2O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)(2)(H(2)dcbpy)] (1NN center dot 3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H(2)dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS center dot H2O to acetone vapor at room temperature, and about 80% of 1SS center dot H2O was found to be converted to 1SN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (lambda(irr) = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H(2)dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN.4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding ability among the carboxyl groups of the H(2)dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular switching function driven by vapor molecules.
  • Kohei Miyata, Tadashi Ohba, Atsushi Kobayashi, Masako Kato, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
    CHEMPLUSCHEM 77 (4) 277 - 280 2192-6506 2012/04 [Refereed][Not invited]
  • Takeshi Matsumoto, Masanori Wakizaka, Hirokazu Yano, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato
    DALTON TRANSACTIONS 41 (27) 8303 - 8315 1477-9226 2012 [Refereed][Not invited]
     
    The redox-active fac-[Mo-V(mp)(3)](-) (mp: o-mercaptophenolato) bearing asymmetric O- and S-cation binding sites can bind with several kinds of metal ions such as Na+, Mn-II, Fe-II, Co-II, Ni-II, and Cu-I. The fac-[Mo-V(mp)(3)](-) metalloligand coordinates to Na+ to form the contact ion pair {Na+(THF)(3)[fac-Mo-V(mp)(3)]} (1), while a separated ion pair, n-Bu4N[fac-Mo-V(mp)(3)] (2), is obtained by exchanging Na+ with n-Bu4N+. In the presence of asymmetric binding-sites, the metalloligand reacts with (MnCl2)-Cl-II center dot 4H(2)O, (FeCl2)-Cl-II center dot 4H(2)O, (CoCl2)-Cl-II center dot 6H(2)O, and (NiCl2)-Cl-II center dot 6H(2)O to afford UV-vis-NIR spectra, indicating binding of these guest metal cations. Especially, for the cases of the MnII and CoII products, trinuclear complexes, {M(H2O)(MeOH)-[ fac-Mo-V(mp)(3)](2)}center dot 1.5CH(2)Cl(2) (3.1.5CH(2)Cl(2) (M = Mn-II), 4.1.5CH(2)Cl(2) (M = Co-II)), are successfully isolated and structurally characterized where the M are selectively bound to the hard O-binding sites of the fac-[Mo-V(mp)(3)](-). On the other hand, a coordination polymer, {Cu-I(CH3CN)[mer-MoV(mp)(3)]}(n) (5), is obtained by the reaction of fac-[Mo-V(mp)(3)]-with [Cu-I(CH3CN)(4)]ClO4. In sharp contrast to the cases of 1, 3.1.5CH(2)Cl(2), and 4.1.5CH(2)Cl(2), the Cu-I in 5 are selectively bound to the soft S-binding sites, where each CuI is shared by two [MoV(mp) 3]-with bidentate or monodentate coordination modes. The second notable feature of 5 is found in the geometric change of the [MoV(mp) 3]-, where the original fac-form of 1 is isomerized to the mer-[Mo-V(mp)(3)](-) in 5, which was structurally and spectroscopically characterized for the first time. Such isomerization demonstrates the structural flexibility of the [Mo-V(mp)(3)](-). Spectroscopic studies strongly indicate that the association/dissociation between the guest metal ions and metalloligand can be modulated by solvent polarity. Furthermore, it was also found that such association/dissociation features are significantly influenced by coexisting anions such as ClO4- or B(C6F5)(4)(-). This suggests that coordination bonds between the guest metal ions and metalloligand are not too static, but are sufficiently moderate to be responsive to external environments. Moreover, electrochemical data of 1 and 3.1.5CH(2)Cl(2) demonstrated that guest metal ion binding led to enhance electron-accepting properties of the metalloligand. Our results illustrate the use of a redox-active chalcogenolato complex with a simple mononuclear structure as a multifunctional metalloligand that is responsive to chemical and electrochemical stimuli.
  • Hua-Xin Zhang, Masako Kato, Yoichi Sasaki, Tadashi Ohba, Hiroto Ito, Atsushi Kobayashi, Ho-Chol Chang, Kohei Uosaki
    DALTON TRANSACTIONS 41 (37) 11497 - 11506 1477-9226 2012 [Refereed][Not invited]
     
    Dinuclear complexes [{Pt(trpy)}(2)(L)](PF6)(2) (trpy = 2,2': 6',2 ''-terpyridine, L = 2-octylthio-1,3,5-triazine4,6- dithiolate ion (1), L = 2-octadecylthio-1,3,5-triazine-4,6-dithiolate ion (2), L = 2-di-n-butylamino1,3,5- triazine-4,6-dithiolate ion (3)) and a trinuclear complex [{Pt(trpy)}(3)(L)](PF6)(3) (L = 1,3,5-triazine2,4,6- trithiolate ion (4)) have been synthesized and characterized. The single crystal X-ray analysis revealed that the two {Pt(trpy)}(2+) fragments in 1 and 3 adopt a syn-configuration. The Pt...Pt distances are around 4.3 angstrom, suggesting no intramolecular Pt...Pt interactions. Complexes 1-4 in acetonitrile show broad absorption bands at around 470 nm, assigned to mainly the ligand-to-ligand charge transfer ((LLCT)-L-1) from triazine thiolates to trpy based on the comparison to the related complexes and the density functional theory (DFT) calculations. The red luminescence of 1-4 in acetonitrile is attributable to emission predominantly from (LLCT)-L-3. Cyclic voltammograms of 1-3 exhibit four redox couples from -2.0 V to 0 V vs. Ag/AgCl. The two consecutive processes at around -0.70 V are assigned to the sequential reduction of two trpy ligands. This assignment was further supported by the observation of the anion radical of trpy in spectroelectrochemical experiments. The splitting of the redox potentials of two trpy ligands evidences the moderate electronic coupling interactions mediated by the triazine dithiolate bridges. Complex 2 formed a transparent red gel in CH3CN, whereas 4 produced a gel-like solid in the mixtures of CH3CN and other solvents. The interactions dominating the aggregative behaviours have been discussed based on the results of electronic absorption and emission spectroscopy.
  • Coordination site-Dependent Cation Binding and Multi-responsible Redox Properties of Janus-Head Metalloligand, [MoV(1,2-mercaptophenolato)3]-
    Dalton. Trans. 41 8201 - 8478 2012 [Refereed][Not invited]
  • Atsushi Kobayashi, Hirofumi Hara, Tsubasa Yonemura, Ho-Chol Chang, Masako Kato
    DALTON TRANSACTIONS 41 (6) 1878 - 1888 1477-9226 2012 [Refereed][Not invited]
     
    Reactions of a Pt(II)-diimine-based metalloligand Na-2[Pt(CN)(2)(4,4'-dcbpy)] (4,4'-H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) with alkaline-earth metal salts Mg(NO3)(2)center dot 6H(2)O, CaCl2, SrCl2 center dot 6H(2)O, and BaBr2 center dot 2H(2)O in aqueous solution gave luminescent complexes formulated as [Mg(H2O)(5)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 4H(2)O (MgPt-4 center dot 9H(2)O), {[Ca(H2O)(3)][Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (CaPt-4 center dot 6H(2)O), {[Sr(H2O)(2)][Pt(CN)(2)(4,4'-dcbpy)]center dot H2O}(infinity) (SrPt-4 center dot 3H(2)O), and {[Ba(H2O)(2)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (BaPt-4 center dot 5H(2)O), respectively. The crystal structures of all MPt-4 complexes were determined by X-ray crystallography. In these structures, the alkaline-earth metal ions are commonly coordinated to the carboxyl groups of the [Pt(CN)(2)(4,4'-dcbpy)](2-) metalloligand. In the case of MgPt-4 center dot 9H(2)O, the Mg(II) ion is bound by five water molecules and one oxygen atom of a carboxyl group to form a neutral complex molecule [Mg(H2O) 5][Pt(CN)(2)(4,4'-dcbpy)]. In contrast, the alkaline-earth metal ion and metalloligand form two-dimensional (CaPt-4 center dot 6H(2)O) and three-dimensional (SrPt-4 center dot 3H(2)O and BaPt-4 center dot 5H(2)O) coordination networks, respectively. All fully hydrated complexes exhibited a strong phosphorescence from the triplet pi-pi* transition state. Luminescence spectroscopy revealed that MgPt-4 center dot 9H(2)O exhibited interesting multichromic (i.e., thermo-, mechano-, and vapochromic) luminescence, whereas CaPt-4 center dot 6H(2)O showed only thermochromic luminescence. The other two complexes did not exhibit any chromic behaviour. Combination analysis of powder X-ray diffraction, thermogravimetry, and IR spectroscopy suggests that the dimensionality of the coordination network contributes considerably to both the structural flexibility and luminescence properties; that is, the low-dimensional flexible coordination network formed in MPt-4 complexes with smaller alkaline-earth metal ions enables a structural rearrangement induced by thermal and mechanical stimuli and vapour adsorption, resulting in the observed multichromic behaviour.
  • Mee Chang, Atsushi Kobayashi, Ho-Chol Chang, Kiyohiko Nakajima, Masako Kato
    CHEMISTRY LETTERS 40 (12) 1335 - 1337 0366-7022 2011/12 [Refereed][Not invited]
     
    A new copper(II)-hydrazone complex, [Cu(paph)Cl(CH3-OH)] (Hpaph: 2-pyridinecarboxaldehyde 2-pyridylhydrazone) (1) has been synthesized and characterized by single-crystal X-ray diffraction and UV-vis spectroscopy. This complex shows distinctive color changes by the protonation/deprotonation and exhibits interesting ON OFF switching of solvatochromic behavior on the basis of the protonation/deprotonation of the hydrazone moiety.
  • Mee Chang, Atsushi Kobayashi, Kiyohiko Nakajima, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 50 (17) 8308 - 8317 0020-1669 2011/09 [Refereed][Not invited]
     
    We describe the novel synthesis of a bis(hydrazone)iron(B) complex in protonated [Fe(Hpbph)(2)]Cl-2 (1) and deprotonated [Fe(pbph)(2)] (2) forms and several hydrogen-bonded proton-transfer (HBPT) assemblies having different dimensionalities of hydrogen-bonded network structures, [Fe(Hpbph)2] (CA)center dot 2CH(3)OH (3), [Fe(Hpbph)(2)](HCA)(2)center dot 2THF (4), and [Fe(Hpbph)(2)](CA)(H(2)CA)(2)center dot 2CH(3)CN (5) (Hpbph = 2-(diphenylphosphino)benzaldehyde-2-pyridylhydrazone), consisting of a deprotonated Fe(II)-hydrazone complex (2) as a proton acceptor (A) and chloranilic acid (H2CA) as a proton donor (D). The deprotonated complex 2 exhibited two-step reversible protonation reactions to form the double-protonated form 1, and the acid-dissociation constants were determined to be 7.6 and 10.3 in methanol solution. Utilizing this proton-accepting ability of 2, we succeeded in synthesizing HBPT assemblies 3, 4, and 5 from the reactions in CH3OH, THF, and CH3CN, respectively, with the same D/A ratio of H(2)CA/[Fe(pbph)(2)] = 10:1. These assemblies were found to have one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) hydrogen-bonded networks with D/A ratios of 1:1, 2:1, and 3:1 for 3, 4, and 5, respectively. In 3, a 1-D hydrogen-bonded chain composed of the alternate arrangement of [Fe(Hpbph)(2)](2+) and CA(2-), {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot CA(2-)center dot center dot center dot}(infinity), was surrounded by solvated methanol molecules to form isolated 1-D hydrogen-bonded chains. In the HBPT assembly 4, a 2-D hydrogen-bonded sheet was formed from two types of hydrogen-bonded chains, {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity) and {center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity), and solvated THF molecules did not form any hydrogen bonds. In 5, two orthogonal hydrogen-bonded chains constructed from the neutral chloranilic acid molecules, {center dot center dot center dot CA2(-)center dot center dot center dot 2(H(2)CA)center dot center dot center dot}(infinity), were formed in addition to the 1-D hydrogen-bonded chain similar to that in 3, resulting in the formation of a rigid 3-D hydrogen-bonded network structure. By controlling the dimensionality of the hydrogen bond network, we found that the 2-D HBPT assembly 4 is sufficiently flexible to exhibit interesting vapochromic behavior in response to various organic vapors.
  • Ho-Chol Chang, Kazuki Komasaka, Keisuke Kishida, Tomoki Shiozaki, Takeshi Ohmori, Takeshi Matsumoto, Atsushi Kobayashi, Masako Kato, Susumu Kitagawa
    INORGANIC CHEMISTRY 50 (10) 4279 - 4288 0020-1669 2011/05 [Refereed][Not invited]
     
    Liquid crystalline (LC) platinum(II) complexes with 1,2-thiophenolato and 1,2-benzendithiolato have been newly synthesized and investigated by spectroscopy together with the catecholato analogue. The variations in coordinating atoms (O or S or O/S mixed) lead to significant modulation in electrochemical properties in solution and absorption and emission properties of the complexes both in solution media and in the condensed phases. The asymmetric, polar mesogens/chromophores consisting of Pt(II), redox-active ligands, and alkyl-substituted bipyridine commonly play important roles not only in stabilizing the columnar LC phases, but also in fluctuations of the ground state energies. A key finding of the present work is the chromic properties of LC complexes induced by the interplay of self-association of the mesogens/chromophores and their fluctuating properties.
  • Takeshi Matsumoto, Ho-Chol Chang, Atsushi Kobayashi, Kohei Uosaki, Masako Kato
    INORGANIC CHEMISTRY 50 (7) 2859 - 2869 0020-1669 2011/04 [Refereed][Not invited]
     
    The synthesis and characterization of two coordination polymers, {Cu[Mo-V(bdt)(3)]center dot 0.5Et(2)O)(n) (1.0.5Et(2)O, bdt: o-benzenedithiolato) and {Ag-I[Mo-V(bdt)(3)]}(n) (2), composed of redox-active [Mo-V(bdt)(3)](-) metalloligand with Cu-I and Ag-I ions are reported. The complexation reactions of [Mo-V(bdt)(3)](-) with Cu-II(ClO4)(2) or (AgClO4)-Cl-I commonly lead to the formation of one-dimensional (1-D) coordination polymers. The presence of Cu-I in 1.0.5Et(2)O strongly indicates that the Cu-II ion is reduced during the complexation reaction with [Mo-V(bdt)(3)](-), which acts as an electron donor. The total dimensionalities of the assembled structures of 1.0.5Et(2)O and 2 are significantly different and related to the type of additional metal ions, Cu-I and Ag-I In contrast to the isolated 1-D chain structure of 1.0.5Et(2)O, complex 2 has a three-dimensional (3-D) assembled structure constructed from additional pi-pi stacking interactions between adjacent [Mo-V(bdt)(3)](-) moieties. These structural differences influence the solubility of the complexes in organic solvents; complex 1.0.5Et(2)O is soluble as origomeric species in highly polar solvents, while 2 is insoluble in organic solvents and water. Coordination polymers 1.0.5Et(2)O and 2 were investigated by UV-vis spectroscopy in the solid state, and that in solution together with their electrochemical properties were also investigated for 1 because of its higher solubility in polar organic solvents. Complex 1 0.5Et(2)O dissolved in CH3CN demonstrates concentration-dependent UV-vis spectra supporting the presence of coordinative interactions between [Mo-V3(bdt)(3)](-) moieties and Cu-I ions to create the origomeric species even in solutions, an observation that is supported also by electrochemical experiments.
  • Atsushi Kobayashi, Yui Suzuki, Tadashi Ohba, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato
    INORGANIC CHEMISTRY 50 (6) 2061 - 2063 0020-1669 2011/03 [Refereed][Not invited]
     
    We synthesized new porous coordination polymers (PCPs) {Ln(III)[Co(III)(dcbpy)(3)]center dot nH(2)O} (Ln = Nd(3+), Gd(3+); H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and characterized them by X-ray diffraction and vapor-adsorption measurements. These three Ln-Co-based PCPs have similar rock-salt types and highly symmetrical porous structure and show a reversible structural collapse regeneration accompanied by water-vapor desorption adsorption. Similar structural regeneration was also observed for the Gd-Co PCP upon exposure to MeOH and CH(3)CN vapors, whereas the remaining two PCPs barely responded to organic vapors.
  • Rie Aoki, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 84 (2) 218 - 225 0009-2673 2011/02 [Refereed][Not invited]
     
    A series of cyclometalated dinuclear platinum(II) complexes bridged by pyridine-2-thiolate (pyt) ions, [Pt-2(L)(2)-(pyt)(2)] (HL = 2-(p-tolyl)pyridine (Hptpy), 2-(2-thienyl)pyridine (Hthpy), or benzo[h]quinoline (Hbzqn)), as well as their two-electron-oxidized dinuclear platinum(III) complexes, [Pt2Cl2(L)(2)(pyt)(2)], have been synthesized and characterized. The structures and luminescence properties have been investigated by comparing them with those of the corresponding 2-phenylpyridinato (ppy) complex. All divalent complexes have similar dinuclear frameworks, with short Pt center dot center dot center dot Pt distances (ca. 2.85 angstrom), and exhibit similar intense luminescence from the triplet metal metal-to-ligand charge-transfer ((MMLCT)-M-3) state in glassy solutions. However, they provide different luminescence features reflecting their dynamic behaviors in fluid solutions and their intermolecular interactions in the solid state. [Pt-2(bzqn)(2)(pyt)(2)] containing fused aromatic rings exhibits the most sensitive features to the environment, i.e., it shows the most red-shifted luminescence spectrum in the solid state due to the intermolecular pi-pi interaction. However, in fluid solution, it provides very weak luminescence based on a rapid nonradiative deactivation mainly caused by the fluctuation of the intramolecular pi-pi repulsion between the ligands. [Pt-2(Ptpy)(2)(pyt)(2)], on the other hand, is the most stable luminophore, which always exhibits intense luminescence with an almost constant emission maximum independent of its temperature and state.
  • 小林 厚志, 加藤 昌子
    日本結晶学会誌 53 (6) 402 - 408 0369-4585 2011 [Not refereed][Not invited]
  • Atsushi Kobayashi, Korin Ohbayashi, Rie Aoki, Ho-Chol Chang, Masako Kato
    DALTON TRANSACTIONS 40 (14) 3484 - 3489 1477-9226 2011 [Refereed][Not invited]
     
    We synthesized a thiosemicarbazone-functionalized flavin (Fl-(H) TSC: 2-[2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)ethylidene]-hydrazinecarbothioamide) and its Pt(II) complex [Pt(Fl-TSC)(2)], and characterized it using X-ray diffraction, UV-visible absorption and luminescence spectroscopy. X-ray structural analysis for [Pt(Fl-TSC)(2)] revealed that the structure of the isoalloxazine part was almost the same as that in lumiflavin (7,8,10-trimethylisoalloxazine), and the thiosemicarbazone moiety acted as a bidentate ligand to form a PtS2N2 planar conformation. UV-visible absorption and luminescence spectra of these compounds were very similar to those of riboflavin, but the emission intensity and the lifetime decreased considerably. Theoretical calculations suggested that the charge-separated state (Fl(center dot-)-TSC center dot+) contributed to the faster quenching from the (1)pi-pi* emission state.
  • Hirofumi Hara, Atsushi Kobayashi, Shin-ichiro Noro, Ho-Chol Chang, Masako Kato
    DALTON TRANSACTIONS 40 (31) 8012 - 8018 1477-9226 2011 [Refereed][Not invited]
     
    Four new bimetallic coordination polymers (CPs), {M[Pt(CN)(2)(5,5'-dcbpy)]center dot 4H(2)O}(n) (M = Mg(2+), Ca(2+), Sr(2+), Ba(2+); 5,5'-H(2)dcbpy = 5,5'-dicarboxy-2,2'-bipyridine) were synthesized using four alkaline-earth metal ions and a Pt(II)-diimine metalloligand [Pt(CN)(2)(5,5'-H(2)dcbpy)]. All four CPs are isomorphous with the Zn complex, {Zn[Pt(CN)(2)(5,5'-dcbpy)]center dot 4H(2)O}(n), which exhibits effective metallophilic interactions between Pt(II) ions. These CPs exhibited colourful thermochromic behaviour and solid-state solvatochromic-like behaviours when suspended in various solvents. Thermogravimetric analysis and vapour-adsorption measurements revealed that the CPs can reversibly adsorb water and MeOH vapours. The emission energy of the triplet metal-metal-to-ligand charge-transfer ((3)MMLCT) state varied markedly upon guest adsorption/desorption. The chromic and vapour-adsorption properties of these CPs depend strongly on the cross-linking M(2+) ions.
  • Hisako Sato, Kenji Tamura, Rie Aoki, Masako Kato, Akihiko Yamagishi
    CHEMISTRY LETTERS 40 (1) 63 - 65 0366-7022 2011/01 [Refereed][Not invited]
     
    Emission from a cationic cyclometalated iridium(III) complex, Delta- or Lambda-[Ir(ppy)(2)(dmbpy)](+) (Hppy: 2-phenylpyridine and dmbpy: 4,4'-dimethyl-2,2'-bipyridine), adsorbed on a colloidal saponite clay was quenched stereoselectively by chiral [Ru(acac)(3)] (acac: acetylacetonato) in a solution at the overall selectivity factor of K-SVo(Delta-Delta or Lambda-Lambda)/K-SVo(Delta-Lambda) = 1.84 in favor of the pseudo-enantiomeric pair between the emitter and the quencher.
  • Atsushi Kobayashi, Masa-aki Dosen, Mee Chang, Kiyohiko Nakajima, Shin-ichiro Noro, Masako Kato
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 (43) 15286 - 15298 0002-7863 2010/11 [Refereed][Not invited]
     
    We synthesized and investigated a new series of metal-hydrazone complexes, including deprotonated [MX(mtbhp)] and protonated forms [MX(Hmtbhp)](ClO(4)) (M = Pd(2+), Pt(2+); X = Cl(-), Br(-); Hmtbhp = 2-(2-(2-(methylthio)benzylidene)hydrazinyl)pyridine) and hydrogen-bonded proton-transfer (HBPT) assemblies containing [PdBr(mtbhp)] and bromanilic acid (H(2)BA). The mtbhp hydrazone ligand acts as a tridentate SNN ligand and provides a high proton affinity. UV-vis spectroscopy revealed that these metal-hydrazone complexes follow a reversible protonation-deprotonation reaction ([MX(mtbhp)] + H(+) -[MX(Hmtbhp)](+)), resulting in a remarkable color change from red to yellow. Reactions between proton acceptor [PdBr(mtbhp)] (A) and proton donor H(2)BA (D) afforded four types of HBPT assemblies with different D/A ratios: for D/A = 1:1, {[PdBr(Hmtbhp)](HBA)center dot Acetone} and {[PdBr(Hmtbhp)](HBA)center dot 2(1,4-dioxane)}; for D/A = 1:2, [PdBr(Hmtbhp)](2)(BA); and for D/A = 3:2, {[PdBr(Hmtbhp)](2)(HBA)(2)(H(2)BA)center dot 2Acetonitrile}. The proton donor gave at least one proton to the acceptor to form the hydrogen bonded A center dot center dot center dot D pair of [PdBr(Hmtbhp)]+center dot center dot center dot HBA(-). The strength of the hydrogen bond in the pair depends on the kind of molecule bound to the free monoanionic bromanilate OH group. Low-temperature IR spectra (T < 150 K) showed that the hydrogen bond distance between [PdBr(Hmtbhp)](+) and bromanilate was short enough (ca. 2.58 A) to induce proton migration in the [pdgr(Hrhtbhp)](2)(BA) assembly in the solid state. The hydrogen bonds formed not only between [PdBr(Hmtbhp)](+) and HBA(-) but also between HBA(-) and neutral H(2)BA molecules in the {[pdBr(Hmtbhp)](2)(HBA)(2)(H(2)BA)center dot 2Acetonitrile} assembly. The H(2)BA-based flexible hydrogen bond network and strong acidic host structure result in an interesting vapor adsorption ability and vapochromic behavior in this assembly because the vapor-induced rearrangement of the hydrogen bond network, accompanied by changes in pi-pi stacking interactions, provides a recognition ability of proton donating and accepting properties of the vapor molecule.
  • Mee Chang, Hiroyuki Horiki, Kiyohiko Nakajima, Atsushi Kobayashi, Ho-Chol Chang, Masako Kato
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 83 (8) 905 - 910 0009-2673 2010/08 [Refereed][Not invited]
     
    A new series of substituted hydrazone complexes, [Cu(Hpbph)I] (1), [Cu(Hpbph)PPh3]PF6 (2-PF6), [NiCl-(Hpbph)]Cl (3-Cl), [PtCl(Hpbph)]ClO4 (4-ClO4), and [PtCl(pbph)] (4b) (Hpbph = 2-(diphenylphosphino)benzaldehyde 2-pyridylhydrazone) have been synthesized and characterized. X-ray crystallography revealed that the copper(1) complexes adopt pseudo-tetrahedral geometry, while the nickel(II) and platinum(II) complexes provide square-planar forms. All the complexes exhibit distinct color changes on the basis of the deprotonation/protonation on the ligand although their acid/base behaviors are largely different. The acidity constants (pK(a)) in methanol were determined to be 11.4 (1), 12.5 (2), 7.7 (3), and 6.7 (4). The results indicate that the dissociation of the proton on the ligand strongly depends on the ligand deformation controlled by the coordination geometry of the complexes and ancillary ligands also somewhat affect the acidity.
  • Atsushi Kobayashi, Tsubasa Yonemura, Masako Kato
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2010 (17) 2465 - 2470 1434-1948 2010/06 [Refereed][Not invited]
     
    A novel luminescent platinum(II)-diimine complex, Na(2)[Pt(CN)(2)(dcbpy)]center dot nH(2)O (H(2)dcbpy = 4,4 '-dicarboxy-2,2'-bipyridine, n = 2 or 5) was synthesized and investigated by using X-ray diffraction measurements and spectroscopy. Complex Na(2)[Pt(CN)(2)(dcbpy)]center dot 2H(2)O was first obtained as a red amorphous solid (IA) that exhibits bright luminescence at 623 nm. After recrystallization, two crystalline forms, the dihydrate form, 1C, and the pentahydrate form, Na(2)[Pt(CN)(2)(dcbpy)]center dot 5H(2)O (2), were obtained and analyzed by the single-crystal X-ray diffraction method. Upon exposure of the amorphous form 1A to hydrophilic vapours such as those of MeOH and acetone, 1A irreversibly changed to a yellow crystalline solid 1C that showed luminescence at 608 nm with a shoulder at 568 nm. This vapour-induced amorphous-crystalline transformation has never been observed either by exposing 1A to hydrophobic vapours nor by increasing the temperature up to 410 K. IR spectroscopy revealed that the amorphous-crystalline transformation did not involve the adsorption of the vapour. This phenomenon of irreversible structural transformation accompanied by change of luminescence is possibly applicable to vapour history sensors.
  • 金属間相互作用に基づく新たなセンシング錯体の開発
    ファインケミカル Vol. 39 24 - 32 2010 [Not refereed][Not invited]
  • 貴金属フリー・ナノハイブリッド触媒の創製
    化学経済 55 - 60 2010 [Not refereed][Not invited]
  • Ken-ichi Sakai, Sami Takahashi, Ataru Kobayashi, Tomoyuki Akutagawa, Takayoshi Nakamura, Masaaki Dosen, Masako Kato, Umpei Nagashima
    DALTON TRANSACTIONS 39 (8) 1989 - 1995 1477-9226 2010 [Refereed][Not invited]
     
    Zinc(II)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties. The pyridine complex is strongly fluorescent (fluorescence quantum yield Phi = 0.22), giving rise to a significantly Stokes-shifted spectrum. From its thin film photopumped by a nitrogen gas laser, amplified spontaneous emission was observed. These results suggest that the fluorescence occurs by way of excited-state intramolecular proton-transfer (ESIPT) in the hydrogen bond of hqxc. On the other hand, the DMSO complex shows fluorescent intensity (Phi = 0.08) lower than that of the pyridine complex, and shows normal emission in addition to ESIPT emission. From IR measurements for these complexes, it is concluded that axial ligands influence the hydrogen bond strength of the equatorial hqxc ligand via zinc and thus the ESIPT efficiency.
  • Atsushi Kobayashi, Hirofumi Hara, Shin-ichiro Noro, Masako Kato
    DALTON TRANSACTIONS 39 (14) 3400 - 3406 1477-9226 2010 [Refereed][Not invited]
     
    We synthesized a new Pt/Zn-based coordination polymer, {Zn[Pt(CN)(2)(5,5'-dcbpy)]center dot 4H(2)O}(n), (5,5'-H(2)dcbpy = 5,5'-dicarboxy-2,2'-bipyridine), which exhibits reversible colour changes in response to temperature change or exposure to chemical vapours and liquids. Such chromic behaviour shows promise for sensing not only changes in temperature but also for detecting chemical solvents and vapours. The single crystal X-ray structure indicates that one-dimensional coordination polymeric chains formed by an alternating arrangement of [Zn(H(2)O)(3)](2+) and [Pt(CN)(2)(5,5'-dcbpy)](2-) stacked to produce moderate metallophilic interactions between the Pt(II) ions. Thermogravimetric analysis and water vapour adsorption measurements show that both the crystal water and water coordinated to Zn(II) ions can be removed and re-adsorbed reversibly by heating or under vacuum. Emission spectra at various temperatures and/or in the presence of vapours or liquids reveal that the complex exhibits thermochromic and solvatochromic-like behaviours, with the emission band shifting between 616 and 671 nm. IR spectroscopy and powder X-ray diffraction measurements suggest that this multichromic behaviour is a result of the cooperative phenomena of water adsorption/desorption around the Zn(II) ions and the modi. cation of the metallophilic interaction.
  • Atsushi Kobayashi, Yuki Fukuzawa, Shin-ichiro Noro, Takayoshi Nakamura, Masako Kato
    CHEMISTRY LETTERS 38 (10) 998 - 999 0366-7022 2009/10 [Refereed][Not invited]
     
    A simple Pt-II-terpyridine complex [Pt(NCS)(tpy)](SCN) (tpy = 2,2': 6', 2 ''-terpyridine) shows distinct two-step vapochromism from red to yellow through dark red in response to methanol vapor. The adsorption isotherm for methanol vapor reveals that the two-step vapochromic behavior originates from breathing-like structural transformations.
  • Gerile Naren, Ami Yasuda, Masayasu Iida, Masafumi Harada, Toshiharu Suzuki, Masako Kato
    DALTON TRANSACTIONS (28) 5512 - 5522 1477-9226 2009 [Refereed][Not invited]
     
    Europium(III) complexes of N-acyl-DL-alaninates (acyl = acetyl, butanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl and tetradecanoyl), N-octanoyl-DL-phenylalaninate, and N-octanoyl-L-serinate were prepared to understand the effects of alkyl chain length and the type of head group on the formation of glassy states and on the aggregation behaviour in solutions. The acylalaninate complexes had a tendency to form a transparent glass, whereas Eu(ala)(3) (ala = DL-alaninate) was easily crystallized. Of the C2(acetyl)-C14(tetradecanoyl) chains in the ligands, the C4-C8 chains were the most favourable to assume a stable glassy state by solvent vaporization. The europium(III) complexes having an acyl chain of C6 (hexanoyl) or longer exhibited a peak below 2q = 5. due to the presence of a bilayer structure in the glassy state. The octanoylserinate complex easily formed an anisotropic glass by a solvent-cast method, while the octanoylphenylalaninate complex transformed from a transparent glass to an anisotropic glass by an annealing treatment. The trend of glass formation was related with the aggregation behaviour of the complexes in methanol detected by self-diffusion and luminescence properties.
  • Hajime Ito, Tomohisa Saito, Naoya Oshima, Noboru Kitamura, Shoji Ishizaka, Yukio Hinatsu, Makoto Wakeshima, Masako Kato, Kiyoshi Tsuge, Masaya Sawamura
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 130 (31) 10044 - + 0002-7863 2008/08 [Refereed][Not invited]
     
    Reversible mechanotronic luminescence of [(C(6)F(5)Au)(2)(mu-1,4-diisocyanobenzene)] is reported. Grinding of the complex induced a photoluminescent color change, which was restored by exposure to a solvent. This cycle was repeated 20 times with no color degradation in the emissions. Their optical properties, X-ray crystallographic analysis, IR, and XRD measurements strongly suggested that the change in the molecular arrangement is responsible for this mechanochromic property. Intermolecular aurophilic bondings presumably play a key role in the altered emission.
  • Takayuki Michi, Masaaki Abe, Satoru Takakusagi, Masako Kato, Kohei Uosaki, Yoichi Sasaki
    CHEMISTRY LETTERS 37 (6) 576 - 577 0366-7022 2008/06 [Refereed][Not invited]
     
    An in situ approach for rapid growth of multilayers of redox-active triruthenium cluster complexes has been developed under electrochemical potential control of the gold electrode, the formation process being successfully probed by cyclic voltammetry and AFM images.
  • Hiroki Kon, Kiyoshi Tsuge, Taira Imamura, Yoichi Sasaki, Shoji Ishizaka, Noboru Kitamura, Masako Kato
    DALTON TRANSACTIONS (12) 1541 - 1543 1477-9226 2008 [Refereed][Not invited]
     
    The direction of excitation energy migration is reversed in a system composed of {Ru(bpy)(2)}-{pyridylporphyrin}(2) by the addition of a Zn2+ ion. The Zn2+ system shows an excitation-wavelength dependent emission.
  • Masako Kato, Yasuko Shishido, Yukiko Ishida, Shinobu Kishi
    CHEMISTRY LETTERS 37 (1) 16 - 17 0366-7022 2008/01 [Refereed][Not invited]
     
    Luminescent mononuclear bipyridine platinum(II) complexes bearing linear alkyl chains, [Pt(CN)(2)(dC(n)bpy)] (n = 9 and 11) have been prepared and characterized. These complexes are soluble in various organic solvents and exhibit remarkable solvent dependence and concentration dependence of the luminescence at room temperature. Such solvatochromic luminescence is attributed to the formation of the excimer of the platinum complexes.
  • Takanori Nishioka, Shigeru Mitsui, Isamu Kinoshita, Tamami Koshiyama, Masako Kato
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 80 (7) 1357 - 1367 0009-2673 2007/07 [Refereed][Not invited]
     
    A dinucleating ligand consisting of thiopyridyl groups appended to a p-xylene backbone reacts with copper(I) halides to afford dinuclear copper complexes with terminal halogeno ligands, which are in equilibrium with bridging halogeno dicopper complexes formed by rearrangement and loss one of the terminal halogeno ligands. The identity of the products was confirmed by using (HNMR)-H-1 spectroscopy, electrospray ionization mass spectrometry, and X-ray structure analyses.
  • Takanori Suzuki, Ryuuichi Tamaki, Eisuke Ohta, Takashi Takeda, Hidetoshi Kawai, Kenshu Fujiwara, Masako Kato
    TETRAHEDRON LETTERS 48 (22) 3823 - 3827 0040-4039 2007/05 [Refereed][Not invited]
     
    The spiro-acridan/acridinium-based dynamic redox pair (1/2(2+)) transduces the electrochemical input into UV-vis and fluorescence spectra, whereas the 2,2 '-bipyridine units in I works as a bidentate ligand for metal ions. X-ray structural analyses of this redox pair and the corresponding Zn-complexes [1-ZnI2/2(2+)-Zn2+(OTf-)(4)] demonstrate drastic structural changes upon electron-transfer, thus metal binding properties are modified by redox reactions. (C) 2007 Elsevier Ltd. All rights reserved.
  • Masako Kato
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 80 (2) 287 - 294 0009-2673 2007/02 [Refereed][Not invited]
     
    Square-planar platinum(II) complexes often exhibit intense color and luminescence when they are stacked via self-assembly or bridging by ligands. The origin of the color and luminescence are the metal-metal electronic interactions, and thus, remarkable changes in color (i.e., chromism) are expected by controlling the Pt center dot center dot center dot Pt interactions. The molecular arrangement of the assembled complex systems is sensitive to environmental factors such as temperature, pressure, solvent, and vapor. This account focuses on the sensing functionalities of luminescent platinum(II) complexes with 2,2'-bipyridine or its derivatives toward their environment. Especially, luminescence changes that are induced by the vapor molecules will be examined from the viewpoint of chemical sensing. The vapochromic behavior and structural aspects of the mononuclear and dinuclear platinum(II) complexes are discussed.
  • Yoshizawa K, Toyota S, Toda F, Kato M, Cs{\"o}regh I
    CrystEngComm 9 (9) 1 - 7 2007 [Refereed][Not invited]
  • WZ Chen, FH Liu, DJ Xu, K Matsumoto, S Kishi, M Kato
    INORGANIC CHEMISTRY 45 (14) 5552 - 5560 0020-1669 2006/07 [Refereed][Not invited]
     
    The neutral square-planar complexes [Pt(RNH2)(2)((NHCOBu)-Bu-t)(2)] (R = H, 1; Et, 2) and [Pt(DACH)((NHCOBu)-Bu-t)(2)] (DACH = 1,2-diaminocyclohexane, 3) act as metalloligands and make bonds to closed-shell Tl(I) ions to afford one- and two-dimensional platinum-thallium oligomers or polymers based on heterobimetallic backbones. A series of heteronuclear platinum(II)-thallium(I) complexes have been synthesized and structurally characterized. The structures of the Pt-Tl compounds resulted from [Pt(RNH2)(2)((NHCOBu)-Bu-t)(2)] and TlX [X = NO3-, ClO4-, PF6-, and Cp2Fe(CO2)(2)(2-)] are dependent on both counteranions and the amine substituents. The compounds [Pt(NH)(2)((NHCOBu)-Bu-t)(2)Tl]X (X = NO3-, 8; ClO4-, 9) adopt one-dimensional zigzag chain structures consisting of repeatedly stacked [Pt(NH3)(2)-((NHCOBu)-Bu-t)(2)Tl](+) units, whereas [{Pt(NH3)(2)((NHCOBu)-Bu-t)(2)}(2)Tl-2]X-2 (X = PF6-, 10) consists of a helical chain. Compound 3 reacts with Tl+ to give [{Pt(DACH)( (NHCOBu)-Bu-t)(2)}(2)Tl](NO3)center dot[Pt(DACH)((NHCOBu)-Bu-t)2]center dot 3H(2)O (14) and one-dimensional polymeric [{Pt(DACH)((NHCOBu)-Bu-t)(2)}(2)Tl-2]X-2 (X = ClO4-, 15; PF6-, 16). Reactions of [Pt(DACH)(NHCOCH3)(2)] with Tl+ ions afford one-dimensional coordination polymers [{Pt(DACH)(NHCOCH3)(2)}(2)Tl-2] X2 (X = NO3-, 17; ClO4-, 18; PF6(-), 19). The polymeric [{Pt(DACH)(NHCOR')(2)}(2)Tl-2](2+) (R = CH3, Bu-t) complexes adopt helical structures, which are generated around the crystallographic 2(1) screw axis. The distance between the coils corresponds to the unit cell length, which ranges from 22.58 to 22.68 angstrom. The platinum-thallium bond distances fall in a narrow range around 3.0 angstrom. The complexes derived from [Pt(NH3)(2)((NHCOBu)-Bu-t)(2)] are luminescent at 77 K. The trinuclear complexes [{Pt(RNH2)((NHCOBu)-Bu-t)(2)}(2)Tl](+) do not emit at room temperature but are emissive at 77 K, whereas the polymeric platinum-thallium complexes containing 1,2- diaminocyclohexane are intensively luminescent at both room temperature and 77 K. The color variations are interesting; 15 exhibits intense yellow-green, 16 exhibits green, and 17-19 exhibit blue luminescence. The presence of bonding between platinum and thallium is supported by the short metal-metal separations and the strong low-energy luminescence of these compounds in their solid states.
  • M Kato, Y Okada, Y Shishido, S Kishi
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 62 (5) M171 - M173 0108-2701 2006/05 [Refereed][Not invited]
     
    Dichloro-(4,4'-dipentyl-2,2'-bipyridine-kappa N-2,N')platinum(II), [PtCl2(C20H28N2)], adopts a discrete pi-pi stacking structure, where the alkyl chains are located in a random manner. In contrast, dichloro-(4,4'-diheptyl-2,2'-bipyridine-kappa N-2,N')platinum(II), [PtCl2(C24H36N2)], forms a layer structure comprised of alkyl chain layers and paired coordination sites, as observed for analogous complexes with longer alkyl chains.
  • Y Sugimoto, M Matsui, H Takikawa, M Sasaki, M Kato
    PHYTOCHEMISTRY 66 (22) 2627 - 2631 0031-9422 2005/11 [Refereed][Not invited]
     
    Dechlorodauricumine, a possible organic substrate for biochlorination, was isolated from cultured roots of Menispermum dauricum, a rich source of chlorinated alkaloids. Its structure was established by spectroscopic and chemical methods. (c) 2005 Elsevier Ltd. All rights reserved.
  • M Kato, S Kishi, Y Wakamatsu, Y Sugi, Y Osamura, T Koshiyama, M Hasegawa
    CHEMISTRY LETTERS 34 (10) 1368 - 1369 0366-7022 2005/10 [Refereed][Not invited]
     
    Dicyano(4,4'-dicarboxy-2,2'-bipyridine)platinum(II) forms pH-dependent polymorphs of various colors and displays outstanding vapochromism followed by luminescence changes upon exposure to certain organic vapors. The high sensitivity of the complex to vapor and pH is related to its three-dimensional network structure, which includes large cavities formed by hydrogen bonds and Pt center dot center dot center dot Pt interactions.
  • T Koshiyama, M Kato
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 61 (4) M173 - M176 0108-2701 2005/04 [Refereed][Not invited]
     
    The title dinuclear platinum(III) complex, [Pt-2(C11H8N)(2)(C5H4NS)(4)], forms two crystal structures, viz. the non-solvated and acetonitrile-solvated (C2H3N) forms. For both forms, two (2-pyridylphenyl) platinum units are bridged by two pyridine-2-thiolate (pyt) anions in a head-to-tail configuration, and the other two pyridine-2-thiolate anions occupy the axial position, coordinated through their S atoms. The most remarkable difference between the two forms is the orientation of the axial monodentate ligands. Those for the solvated form are located over the 2-pyridylphenyl ligands, being related by a twofold axis which lies through the centre of the Pt-Pt bond, while the axial pyt ligands for the non-solvated form are oriented irregularly, which is attributable to the dimeric arrangement in the crystal.
  • K Saito, Y Hamada, H Takahashi, T Koshiyama, M Kato
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 (16-19) L500 - L501 0021-4922 2005 [Refereed][Not invited]
     
    Electroluminescent properties of an emissive binuclear platinum(l]) complex have been studied. We fabricated organic light-emitting diodes based on Pt-2(ppy)(2)(pyt)(2) (ppy = 2-phenylpyridine, pyt = pyridine-2-thiolate) phosphor, which exhibits an emission from a (MMLCT)-M-3 state based on a Pt-Pt interaction. An electrophosphorescent device with a multilayer configuration of ITO/CuPc/NPB/Pt-2(ppy)(2)(pyt)(2)/BAlq/Alq(3)/LiF/Al demonstrated red emission with Commission Internationale de L'Eclairage (CIE) coordinates of x = 0.65, y = 0.35, a maximum luminous efficiency of 1.8 cd/A (1.0 mA/cm(2)), and an external quantum efficiency of 3.4%.
  • Yoshizawa K, Toyota S, Toda F, Chatziefthimiou S, Giastas P, Mavridis I.M, Kato M
    Angewandte Chemie - International Edition 44 (32) 2 - 4 2005 [Refereed][Not invited]
  • S Hirano, S Toyota, M Kato, F Toda
    CHEMICAL COMMUNICATIONS (29) 3646 - 3648 1359-7345 2005 [Refereed][Not invited]
     
    The axial conformers of chloro- and bromocyclohexane were isolated in a pure state as inclusion complexes with 9,9'-bianthryl, and a 1,3 diaxial Cl center dot center dot center dot H weak interaction was discovered by X-ray analysis of the axial conformer of chlorocyclohexane.
  • K Kobayashi, H Sato, S Kishi, M Kato, S Ishizaka, N Kitamura, A Yamagishi
    JOURNAL OF PHYSICAL CHEMISTRY B 108 (48) 18665 - 18669 1520-6106 2004/12 [Refereed][Not invited]
     
    When a chloroform solution of a dicyano(diimine)platinum(II) complex, [Pt(CN)(2)(5,5'-dinonyl-2,2'-bipyfidine)], was spread onto pure water, a reversible surface pressure- molecular area curve was obtained. The surface pressure began to increase steeply from 0 at a molecular area of 0.61 nm(2) molecule'. On further compression, the iTionolayer was stable at 0.2 nm(2) molecule' and 30 mN m(-1). In such a highly compressed state, the complex was thought to orient its planar ligand 2,2'-bipyridine perpendicular to the water surface. The floating monolayer was vertically deposited onto a hydrophobic quartz substrate as an X-type film. The absorption spectra of the deposited filins showed a broad peak at 480 nm, while that band was absent in the solution spectrum. The emission spectra of the films exhibited a broad band around 600 nm. The excitation spectra monitored at 600 nm coincided well with the absorption spectra. The results were interpreted in terms of the formation of the molecular aggregate, in which the platinum complexes were stacked with the overlaying bipyridine moieties. In such an aggregate, the MMLCT state was generated due to the Pt-Pt interaction among the neighboring molecules. On the basis of the model, the absorption band at 480 nm and the emission band at 600 nm were assigned to the (MMLCT)-M-1 and (MMLCT)-M-3 transitions from or to the dsigma* orbital of Pt(II) to or from the pi* orbital of 2,2'-bipyridine, respectively. The AFM observation showed that the film deposited on a silicon wafer consisted of a grain-shaped aggregate, assisting the intermolecular interactions of composite molecules.
  • T Koshiyama, A Omura, M Kato
    CHEMISTRY LETTERS 33 (10) 1386 - 1387 0366-7022 2004/10 [Refereed][Not invited]
     
    A cyclometalated dinuclear platinum(II) complex bridged with pyridine-2-thiolate ions, [Pt-2(ppy)(2)(ppy)(2)] (Hppy = 2-phenylpyridine, Hpyt = pyridine-2-thiol) and its oxidized platinum(III) complex, [Pt2Cl2(ppy)(2)(pyt)(2)] have been synthesized and characterized. The divalent complex exhibits intense red luminescence both in solution and in the solid states. Corresponding to the short (PtPt)-Pt-... distance (2.849(1)Angstrom) for [Pt-2(ppy)(2)(pyt)(2)], the reversible conversion between the divalent and trivalent complexes occurs easily with appearance and disappearance of the luminescence.
  • M Nakai, M Obata, F Sekiguchi, M Kato, M Shiro, A Ichimura, Kinoshita, I, M Mikuriya, T Inohara, K Kawabe, H Sakurai, C Orvig, S Yano
    JOURNAL OF INORGANIC BIOCHEMISTRY 98 (1) 105 - 112 0162-0134 2004/01 [Refereed][Not invited]
     
    Two chargeless VO(IV) complexes with 3-hydroxypyridine-2-carboxylic acid (H(2)hpic), [VO(Hhpic-O,O)(Hhpic-O,N)(H2O)(.)3H(2)O (1) and the cyclic tetramer [(VO)4(mu-(hpic-O,O,N))(4)(H2O)(4)](.)8H(2)O (2), have been synthesized and characterized by elemental analysis, mass, infrared, electronic absorption, electron spin resonance (ESR) spectroscopies, and X-ray crystallography. Their coordination structures are similar to each other (and 1 is readily transformed into 2), but are quite different from that of bis(pyridine-2-carboxylato)oxovanadium(IV). The magnetic susceptibility of 2 indicates the presence of a weak ferromagnetic intramolecular interaction between the V atoms at low temperature, in addition to a weak antiferromagnetic intermolecular interaction. The ESR signal of 2 was broad, while I showed an eight-line hyperfine splitting pattern due to coupling of the impaired electron with the V-51 nucleus (I = 7/2). The ESR spectrum and cyclic voltammogram of 2 clearly show that the cyclic tetramer remains intact in solution. The insulinomimetic activity of 1 and 2 was evaluated by means of in vitro measurements of the inhibition of free fatty acid release from epinephrine-treated isolated rat adipocytes. While I exerted higher insulinomimetic activity than VOSO4, the activity of 2 was significantly lower than that of VOSO4. Hence 2 appears to retain its cyclic structure during the in vitro test. These results indicate that the rational ligand design for VO complexes might be a promising approach to obtain superior insulinomimetic activity. (C) 2003 Elsevier Inc. All rights reserved.
  • S Kishi, M Kato
    INORGANIC CHEMISTRY 42 (26) 8728 - 8734 0020-1669 2003/12 [Refereed][Not invited]
     
    Three linkage isomers, bis(thiocyanato-S)(2,2'-bipyridine)platinum(II) ([Pt(SCN)(2)(bpy)]), (thiocyanato-S)(thiocyanato-N(2,2'-bipyridine)platinum(II) ([Pt(SCN)(NCS)(bpy)]), and bis(thiocyanato-M(2,2'-bipyridine)platinum(II) ([Pt(NCS)(2)(bpy)]) were isolated, and their structures were elucidated. The crystal data are as follows: for [Pt(SCN)(2)(bpy)), C12H8N4S2Pt, orthorhombic, P2(1)2(1)2(1) (No. 19), a = 12.929(g) Angstrom, b = 18.67(1) Angstrom, c = 5.497(4) Angstrom, Z = 4; for [Pt(SCN)(NCS)(bpy)], C12H8N4S4Pt, monoclinic, P2(1)/n (No. 14), a = 10.909(7) Angstrom, b = 7.622(4) Angstrom, c = 16.02(l) Angstrom, beta = 102.323(7)degrees, Z = 4; for [Pt(NCS)(2)(bpy)], C12H8N4S4Pt, orthorhombic, Pbcm (No. 57), a = 10.3233(8) Angstrom, b = 19.973(2) Angstrom, c = 6.4540(5) Angstrom, Z = 4. The stacking structures of the isomers were found to be different depending on the coordination geometries based on the N- and S-coordination of the thiocyanato ligands, which control the color and luminescence of the crystals sensitively. The isomerization behaviors of the complex have been investigated both in solution and in the solid state. In solution, stepwise thermal isomerization from [Pt(SCN)(2)(bpy)] to [Pt(NCS)(2)(bpy)] by way of [Pt(SCN)(NCS)(bpy)] was observed using H-1 NMR spectroscopy. Reverse isomerization, from [Pt(NCS)(2)(bpy)] to [Pt(SCN)(NCS)(bpy)] and [Pt(SCN)(2)(bpy)], occurred when irradiated with near ultraviolet (UV) light. In contrast, the [Pt(SCN)(2)(bpy)] yellow crystals exhibited thermal isomerization directly to red crystals of [Pt(NCS)(2)(bpy)), as detected by changes in the emission spectrum, which indicates that the flip of two SCN- ligands correlatively occurred in the solid state. The yellow crystals of [Pt(SCN)(NCS)(bpy)] were also converted to the thermodynamically stable red crystal of [Pt(NCS)(2)(bpy)] though the reverse isomerization has never been observed to occur by photoirradiation in the solid state.
  • T Koshiyama, M Kato
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 59 (11) M446 - M449 0108-2701 2003/11 [Refereed][Not invited]
     
    The title Pt-II complexes, viz. (2,2'-bipyridine-kappa(2)N,N')[(1R,2R)1,2-diaminocyclohexane-kappa(2)N,N']platinum(II) bis(hexafluorophosphate), [Pt(C6H14N2)(C10H8N2)](PF6)(2), and [(1R,2R)1,2-diaminocyclohexane-kappa(2) N,N'] (1,10-phenanthroline-kappa(2)N,N')platinum(II) bis(hexafluorophosphate), [Pt(C6H14N2)(C12H8N2)] (PF6)(2), containing an aromatic alpha-diimine and a nonplanar diaminocyclohexane, both form a ladder-type structure, which is constructed via loose pi-pi stacking on the alpha-diimine ligands and hydrogen bonding between the cyclic amines and the counter-anions. In the former compound, there are two independent complex cations, both of which have a twofold axis through the Pt atom.
  • K Tanaka, T Watanabe, M Kato
    JOURNAL OF CHEMICAL RESEARCH-S (9) 535 - 537 0308-2342 2003/09 [Refereed][Not invited]
     
    Inclusion crystals of 7-bromo-1,4,8-triphenyl-2,3-benzo[3.3.0]octa-2,4,7-trien-6-one (1a) and its chloro-derivative (1b) showed a reversible colour change from yellow to green on exposure to UV-light, and this depends on the guest molecules present. The crystal structures of the inclusion complex were determined by X-ray analysis.
  • N Yasuda, Y Sugimoto, M Kato, S Inanaga, K Yoneyama
    PHYTOCHEMISTRY 62 (7) 1115 - 1119 0031-9422 2003/04 [Refereed][Not invited]
     
    (+)-Strigol was isolated from Menispermum dauricum root culture filtrate. Its identity was confirmed by HPLC, H-1 NMR, UV and MS, and on the basis of its CD spectrum. This is the first report on isolation of strigolactone from aseptic plant culture. (C) 2003 Elsevier Science Ltd. All rights reserved.
  • T Suzuki, T Kuchiyama, S Kishi, S Kaizaki, HD Takagi, M Kato
    INORGANIC CHEMISTRY 42 (3) 785 - 795 0020-1669 2003/02 [Refereed][Not invited]
     
    Several new ruthenium(II) complexes containing 8-(dimethylphosphino)quinoline (Me(2)Pqn) were synthesized, and their structures and electrochemical/spectroscopic properties have been investigated. In addition to the mono(Me2Pqn) complex [Ru(bpy or phen)(2)(Me(2)Pqn)](PF6)(2) (1 or 1'; bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline), the geometrical isomers trans(P)- and C-1-[Ru(bpy)(Me(2)Pqn)(2)](PF6)(2) (tP-2 and C-1-2) and mer- and fac-[Ru(Me(2)Pqn)(3)](PF6)(2) (m-3 and f-3) were also selectively synthesized and isolated. It was found that complexes tP-2 and m-3 were converted quantitatively to the corresponding C1-2 and f-3 isomers, respectively, by irradiation of light corresponding to the MLCT transition energy. The strong trans influence of the Me2P- donor group of Me(2)Pqn was confirmed by the X-ray structural analyses for 1, tP-2, m-3, and f-3. Cyclic voltammetry of a series of complexes, [Ru(bPY)(3)](PF6)(2), 1, C-1-2, and f-3, exhibited a reversible one-electron oxidation wave and two or three one-electron reduction waves. The oxidation potentials of the complexes gave a large positive shift with increasing number of coordinated Me(2)Pqn molecules, indicating a larger pi-acceptability of the Me2P- group compared with bpy or qn. Complex f-3 in EtOH/MeOH (4:1) glass at 77 K exhibited an intense long-lived (T = 920 mus) emission arising from the quinoline-based (3)(pi-pi(*)) excited state. In contrast, the mixed-ligand complexes 1, 1', and C-1-2 showed a characteristic dual emission, giving a double-exponential emission decay, and the dual emission originates from both the bpy-based (MLCT)-M-3 and the quinoline-based emitting states.
  • M Kato, M Ikemori
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 59 (1) M25 - M26 0108-2701 2003/01 [Refereed][Not invited]
     
    The title compound, [PtCl2 (C28H44N2)], is a new square-planar Pt-II complex containing a bipyridine moiety with two long alkyl-chain substituents. The complex forms a segregated packing structure made up of the alkyl-chain layers and paired coordination sites.
  • T Suzuki, T Kuchiyama, S Kishi, S Kaizaki, M Kato
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 75 (11) 2433 - 2439 0009-2673 2002/11 [Refereed][Not invited]
     
    Mixed-ligand bis(2,2-bipyridine)ruthenium(II) complexes containing a hybrid donor-type P-N ligand of 8-(diphenylphosphino)quinoline (Ph(2)Pqn) or 2-(diphenylphosphino)pyridine (Ph(2)Ppy), [Ru(bpy)(2)(Ph(2)Pqn or Ph(2)Ppy)](PF6)(2) (1 or 2; bpy = 2,2 -bipyridine), have been prepared. The X-ray crystal structure analyses of 1 and 2 revealed that Ph(2)Pqn and Ph(2)py act as a bidentate ligand to form a five- and four-membered chelate ring, respectively. The four-membered chelate ring formed by Ph(2)Ppy has a very small bite angle (P(1)-Ru-N(1): 68.4(1)degrees), but the Ru-II(bpy)(2) moiety in 2 has a typically strain-free structure. On the other hand, in the Ph2Pqn complex 1, one of the bpy planes is skewed remarkably from the Ru coordination plane due to an intramolecular steric interaction with a phenyl ring of Ph2Pqn. The redox potentials and the (MLCT)-M-1 transition energies of the Ph2Pqn and Ph(2)Ppy complexes (1 and 2) were not so different from the averaged values of those of the corresponding 1,2-bis(diphenylphosphino)benzene (dppb) and 1,10-phenanthroline (phen) complexes, [Ru(bpy)2(dppb or phen)](PF6)2 (3 or 4). These facts indicate that the electronic asymmetry inherently present in Ph2Pqn and Ph(2)Ppy does not affect remarkably the ground state properties of the complexes. However, unlike complexes 2-4, the Ph(2)Pqn complex 1 in EtOH/MeOH (4:1) glass at 77 K exhibited a novel dual emission, giving a biexponential emission decay. The shorter-lived (tau = 10.8 mus) emission is attributable to the bpy-based (MLCT)-M-3 emission, similar to the other Ru-II-polypyridine complexes, while the longer-lived (tau = 62.1 mus) emission can probably be assigned as arising from the quinoline-based (3)(pi-pi*) excited state.
  • S Yano, M Nakai, F Sekiguchi, M Obata, M Kato, M Shiro, Kinoshita, I, M Mikuriya, H Sakurai, C Orvig
    CHEMISTRY LETTERS (9) 916 - 917 0366-7022 2002/09 [Refereed][Not invited]
     
    Reaction of vanadyl sulfate with 3-hydroxypyridine-2-carboxylic acid (H(2)hpic) affords two chargeless complexes, [VO(Hhpic-O,O)(Hhpic-O,N)(H2O)].3H(2)O (1) and unprecedented cyclic tetranuclear complex [(VO)(4)(mu-(hpic-O,O',N))(H2O)(4)].8H(2)O (2), which were characterized by X-ray crystallographic analysis. The unique structural transformation between complexes 1 and 2 was found.
  • F Toda, S Hirano, S Toyota, M Kato, Y Sugio, T Hachiya
    CRYSTENGCOMM 4 (31) 171 - 173 1466-8033 2002/06 [Refereed][Not invited]
     
    Inclusion complexes formed by the title host compound with volatile guests such as dimethyl ether, diethyl ether, acetone and MeOH release the guests at much higher temperatures (108, 114, 128, and 113 degreesC, respectively) than their boiling points. In contrast, the inclusion complexes with the non-volatile guests DMSO and DMF release them at much lower temperatures (121 and 120 degreesC) than their boiling points (189 and 153 degreesC). X-Ray studies reveal that the volatile guests are enclosed tightly by the host molecules, while the non-volatile guests are accommodated solitarily in channels and are easily released through these channels upon heating.
  • M Yagi, S Hirano, S Toyota, M Kato, F Toda
    CRYSTENGCOMM 4 (25) 143 - 145 1466-8033 2002/05 [Refereed][Not invited]
     
    For each of the imidazole equilibrium tautomers mixtures, 2-phenyl-4(5)- and 2-ethyl-4(5)-methylimidazole, 2-phenyl-5- and 2-ethyl-5-imidazole isomers, respectively, were isolated, in a pure state by means of inclusion complexation with a host compound. In the case of 4( 5)- methylimidazole, however, it was the pure 4-methylimidazole tautomer that was isolated as its inclusion complex with the rac-bis-beta-naphthol host. In the latter case, it was found that (+)- and (-)-bis-beta-naphthol molecules form a hydrogen bonded pair, and 4-methylimidazole binds to the host through OH...N and NH...O hydrogen bonds.
  • G Kaupp, J Schmeyers, M Kato, K Tanaka, F Toda
    JOURNAL OF PHYSICAL ORGANIC CHEMISTRY 15 (3) 148 - 153 0894-3230 2002/03 [Refereed][Not invited]
     
    The thermal isomerizations of meso- and rac-3,4-dibromo-1,6-diphenyl-1,6-bis(p-tolyl)-1,2,4,5-hexatetraene (1) to give stereospecifically the 3,4-bis(phenyl-p-tolylmethylene)-1,2-dibromocyclobutenes 3 and 5 + 6 were studied in the solid state using atomic force microscopy (AFM) and interpreted on the basis of known crystal structural data. These isomerizations run to completion in the bulk and include highly space-demanding internal rotations around the central bond. Far-reaching anisotropic molecular movements are detected on the major faces that align the surface features along cleavage planes in the initial phase rebuilding stage. Only one of three identified cleavage planes of meso-1 is successful, owing to closer interactions of the bromine substituents in the non-used cleavage planes. Thus, very fine details can be correlated and predicted for the occurrence of internal rotations and molecular movements in the crystal lattice. The second stage in these intramolecular isomerizations, the phase transformation, produces very high features up to 100 nm and still parallel to the preferred cleavage plane of meso-1 but in the pm range without relation to the initial crystal structure in the case of rac-1. Copyright (C) 2002 John Wiley Sons, Ltd.
  • M Kato, Y Ogawa, M Kozakai, Y Sugimoto
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 58 (3) m147 - m149 0108-2701 2002/03 [Refereed][Not invited]
     
    Bis(8-quinolinolato-N,O)platinum(II), [Pt(C9H6NO)(2)], (I), has a centrosymmetric planar structure with trans coordination. The molecules form an inclined pi stack, with an interplanar spacing of 3.400 (6) Angstrom. 8-Hydroxyquinolinium dichloro(8-quinolinolato-N,O)platinate(II) tetrahydrate, (C9H8NO)[PtCl2 (C9H6NO)].4H(2)O, (II), is soluble in water and is regarded as the synthetic intermediate of the insoluble neutral compound (I). The uncoordinated 8-hydroxyquinolinium cations and the monoquinolinolate complexes form an alternating pi stack. The origins of fluorescence and phosphorescence in (II) are assigned to the 8-hydroxyquinolinium cation and the monoquinolinolate-Pt complex, respectively.
  • Kato M, Omura A, Toshikawa A, Kishi S, Sugimoto Y
    Angewandte Chemie - International Edition 41 (17) 3183 - 3185 2002 [Refereed][Not invited]
  • S Kishi, M Kato
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 379 303 - 308 1058-725X 2002 [Refereed][Not invited]
     
    Vapochromic behavior of the crystal of dicyano(2,2'-bipyridine)platinum(II), [Pt(CN)(2)(bpy)], has been investigated structurally and emission spectroscopically. Red Form with an infinite Pt...Pt chain transforms to Yellow Form reversibly by taking up water vapor. The crystal structure of Yellow Form ([Pt(CN)(2)(bpy)].H2O) was determined by X-ray analysis: the square-planar complexes form the inclined stack with short and long Pt...Pt distances (3.3279(3) and 4.6814(3) Angstrom). The crystal water makes hydrogen bonds with CN- ligands connecting the stacks. The transformation is accompanied by the sensitive luminescence change as well as the color change, which reflects the change of the Pt...Pt electronic interactions. The sensitive vapochromism for this system is attributable to the slight deformation of the stacking structure induced by water molecules.
  • K Tanaka, M Kato, F Toda
    CHIRALITY 13 (7) 347 - 350 0899-0042 2001/07 [Refereed][Not invited]
     
    In order to measure the circular dichroism (CD) spectrum in the solid state of a chiral compound which has no chromophore, an induced CD spectral method was developed by measuring the spectrum of the inclusion crystal of the chiral compound with a simple achiral aromatic host compound in the Nujol mulls. Chirality 13:347-350, 2001. (C) 2001 Wiley-Liss, Inc.
  • G Kaupp, J Schmeyers, M Kato, K Tanaka, N Harada, F Toda
    JOURNAL OF PHYSICAL ORGANIC CHEMISTRY 14 (7) 444 - 452 0894-3230 2001/07 [Refereed][Not invited]
     
    The solid-state thermal transformation of rac-3.8-di(tert-butyl)- 1,5,6,10-tetraphenyldeca-3,4,6,7-tetraene-1,9-diyne (1) into 4,5,9,10-tetraphenyltricyclo[6.2.0.0(2.6)]deca-1,3,5,7,9-pentaene (3) was investigated by x-ray crystallography and atomic force microscopy (AFM) on two different faces. The enantiopure crystals of I that were picked from the conglomerate were monoclinic in the chiral space group C2 (No. 5) and were refined to an R factor of 0,0375. The monolayers stack in a straight manner without displacement leaving (001) cleavage planes. The layered structure is seen in AFM traces at certain stages of the reaction. The overall shape of single crystals of 1 does not change even though they turn deeply blue-green at 140-150 degreesC. However, the initial roughness in the micrometer region is flattened out or thoroughly rearranged by long-range molecular movements giving phase rebuilding and phase transformation without detachment of the product from the parent crystal. Thus. the chemical reaction is limited to the surface region and to internal cracks of the crystal. A topotactical transformation is experimentally excluded and cannot be modelled at the given crystal structure. The chemical yield depends on the crystal size and is significant. The thermochrome 3 reverts to I but only in the outer surface region at anaerobic storage, whereas the known solid-state oxidations occur in air. The topographic differences of these processes were traced with AFM. The release of strain in the surface region is evidenced by anisotropic crack formation that initially follows the crystal packing of 1 and could be imaged and compared with an ordinary microscope after the thermal reversion or oxidation. Copyright (C) 2001 John Wiley & Sons, Ltd.
  • T Tanase, H Inukai, T Onaka, M Kato, S Yano, SJ Lippard
    INORGANIC CHEMISTRY 40 (16) 3943 - 3953 0020-1669 2001/07 [Refereed][Not invited]
     
    Reactions of MCl2. nH(2)O with N,N ' -bis(D-glucopyranosyl)-1,4,7-triazacyclononane ((D-Glc)(2)-tacn), which was formed from D-glucose and 1,4,7-triazacyclononane (tacn) in situ, afforded a series of mononuclear divalent metal complexes with two beta -D-glucopyranosyl moieties, [M{(D-Glc)(2)-tacn}Cl]Cl (M = Zn (11), Cu (12), Ni (13), Co(14)). Complexes 11-14 were characterized by analytical and spectroscopic measurements and X-ray crystallography and were found to have a distorted octahedral M(II) center ligated by the pentacoordinate N-glycoside ligand, (beta -D-glucopyranosyl)(2)-tacn, and a chloride anion. Each D-glucose moiety is tethered to the metal center through the beta -N-glycosidic bond with tacn and additionally coordinated via the C-2 hydroxyl group, resulting in a A-gauche five-membered chelate ring. When L-rhamnose (6-deoxy-L-mannose) was used instead Of D-glucose, the nickel(II) complex with two beta -L-rhamnopyranosyl moieties, [Ni{(D-Man)(2)-tacn}(MeOH)]Cl-2 (15), was obtained and characterized by an X-ray analysis. Reactions of 11 (M = Zn) with [Zn(XDK)(H2O)] (21) or [Cu(XDK)(PY)(2)] (22) (H2XDK = m-xylylenediamine bis(Kemp's triacid imide)) yielded homo, and heterotrimetallic complexes formulated as [Zn2M '{(D-Glc)2-tacn}(2)(XDK)]Cl-2 (M ' = Zn (31), Cu (32)). The similar reactions of 12 (M = Cu) with complex 21 or 22 afforded [Cu2M '{(D-Glc)(2)-tacn}(2)(XDK)]Cl-2 (M ' = Cu (33), Zn (34)). An X-ray crystallographic study revealed that complexes 31 and 34 have either Zn-3(II) or (CuZnCuII)-Zn-II-Cu-II trimetallic centers bridged by two carboxylate groups of XDK and two D-glucopyranosyl residues. The (MM)-M-... ' separations are 3.418(3)-3.462(3) Angstrom (31) and 3.414(1)-3.460(1) Angstrom (34), and the (MM)-M-... ' M-... angles are 155.18(8)degrees (31) and 161.56(6)degrees (34). The terminal metal ions are octahedrally coordinated by the (D-Glc)2-tacn ligand through three nitrogen atoms of tacn, two oxygen atoms of the C-2 hydroxyl groups of the carbohydrates, and a carboxylate oxygen atom of XDK ligand. The central metal ions sit in. a distorted octahedral environment ligated by four oxygen atoms of the carbohydrate residues in the (D-Glc)2-tacn ligands and two carboxylate oxygen atoms of XDK. The deprotonated beta -D-glucopyranosyl unit at the C-2 hydroxyl group bridges the terminal and central ions with the C-2 mu -alkoxo group, with the C-1 N-glycosidic amino and the C-3 hydroxyl groups coordinating to each metal center. Complexes 31-34 are the first examples of metal complexes in which D-glucose units act as bridging ligands. These structures could be very useful substrate binding models of xylose or glucose isomerases, which promote D-glucose D-fructose isomerization by using divalent dimetallic centers bridged by a glutamate residue.
  • Y Sugimoto, HAA Babiker, T Saisho, T Furumoto, S Inanaga, M Kato
    JOURNAL OF ORGANIC CHEMISTRY 66 (10) 3299 - 3302 0022-3263 2001/05 [Refereed][Not invited]
     
    Feeding experiments using Cl-36 showed that Melzispermum,dauricum root culture produces four alkaloids containing chlorine. They included the novel alkaloids dauricumine and dauricumidine as well as the known alkaloids acutumine and acutumidine. The structures of novel alkaloids were established by spectroscopic, crystallographic, and chemical methods. These four alkaloids were labeled with Cl-36, isolated, and fed independently to root cultures. Mutual conversion between acutumine and acutumidine, and between dauricumine and dauricumidine by N-methylation and N-demethylation, was demonstrated. Moreover, dauricumine was converted to acutumine and acutumidine. Epimerization of acutumidine to dauricumidine or vice versa was not observed. These results suggest that dauricumine is the first chlorinated alkaloid formed in cultured M. dauricum roots. Skewed distribution of radioactivity derived from labeled dauricumine is proof that epimerization at C-l proceeds at a lower rate than N-demethylation.
  • K Tanaka, N Takamoto, Y Tezuka, M Kato, F Toda
    TETRAHEDRON 57 (17) 3761 - 3767 0040-4020 2001/04 [Refereed][Not invited]
     
    1,1,2,2-tetraphenyl-3,8-diiodobuta[b]naphthalene (Ic), 1,1,2,2-(2,2'-biphenyl)-3,8-dibromobuta[b]naphthalene (2b), 1,1,2,2(2,2'-biphenyl)-3,8-diiodobuta[b]naphtha (2c), and 1,1,2,2,6,6,7,7-octaphenyl-3,5,8,10-tetracchloro-4,9-dimenthyldicyclobutaanthracene derivatives (3a-3d) were prepared. X-Ray analysis of Ib, Ic, 2c and 3a showed extremely long C-C bond lengths, 1.712 (5), 1.734 (5), 1.724 (5) and 1.726 (7) Angstrom, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.
  • M Kato, K Tanaka, F Toda
    SUPRAMOLECULAR CHEMISTRY 13 (1) 175 - 180 1061-0278 2001 [Refereed][Not invited]
     
    Optically active (R, R)-(-)-trans-1,2-dichlorocyclohexane (DCC) was isolated as an inclusion crystal with the optically active host, 2,3-(hydroxydiphenylmethyl)-1,4-dioxaspiro[4.4]-no-nane, and the structure of the 2:1 inclusion crystal has been determined by ii-ray analysis. Crystal data: C72H74O8Cl2, orthorhombic, P2(1)2(1)2 (No. 18), a = 17.465(6) Angstrom, b = 20.095(6) Angstrom, c = 8.664(5) Angstrom, V = 3040(2) Angstrom (3), Z = 2, D-c = 1.24 g cm(-3), D-m = 1.23 g cm(-3), T = 293 K and final R-1 = 0.050 for 2766 observed data (I > 2 sigma (I)). The conformation of DCC in the inclusion crystal has been found to be equatorial and the absolute configuration was definitely determined to be (R, R) on the basis of the known configuration of the host.
  • Kato M, Takahashi J, Sugimoto Y, Kosuge C, Kishi S, Yano S
    Journal of the Chemical Society, Dalton Transactions (5) 505 - 507 2001 [Refereed][Not invited]
  • K Tanaka, M Kato, F Toda
    HETEROCYCLES 54 (1) 405 - 410 0385-5414 2001/01 [Refereed][Not invited]
     
    A simple optical resolution method of 2-azabicyclo[2.2.1]hept-5-en-3-one by inclusion complexation with brucine was reported. The crystal structure of the inclusion complex was analyzed by X-Ray diffraction in order to elucidate the mechanism of the efficient chiral recognition in the inclusion crystals.
  • T Tanase, N Takeshita, C Inoue, M Kato, S Yano, K Sato
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (15) 2293 - 2302 1472-7773 2001 [Refereed][Not invited]
     
    Reactions of [Ru-2(RCOO)(4)Cl] (R=Me, Ph) with K[HBpz(3)] (HBpz(3)(-)=hydrotris(1-pyrazolyl)borate) afforded the oxo-bridged diruthenium(III) complexes, [Ru-2(mu -O)(mu -RCOO)(2)(HBpz(3))(2)] (R=Me (1a), Ph (1b)) in moderate yields. Complexes 1 were converted by treatment with HPF6 into the hydroxo-bridged diruthenium(III) complexes, [Ru-2(mu -OH)(mu -RCOO)(2)(HBpz(3))(2)](PF6) (R=Me (2a), Ph (2b)), and by reaction with (NH4)(2)Ce(NO3)(6), to the oxo-bridged mixed-valence diruthenium(III, IV) complexes, [Ru-2(mu -O)(mu -RCOO)(2)(HBpz(3))(2)](PF6) (R=Me (3a), Ph (3b)). Complexes 1-3 were characterized by elemental analysis, IR, UV-Vis, and H-1 NMR spectroscopies, and X-ray absorption and crystallographic analyses (1a and 2a). Complex 1a consists of a {Ru-2(mu -oxo)(mu -carboxylato)(2)} core with two terminal face-capping HBpz(3)(-) ligands (Ru . . . Ru=3.2544(7) Angstrom). Protonation of the mu -oxo group of 1a expanded the Ru . . . Ru distance to 3.4490(9) Angstrom, which was elucidated by X-ray crystallography, and one-electron oxidation of 1a also increases this length to 3.38 Angstrom, determined by EXAFS analysis. These complexes interestingly showed, in cyclic voltammograms, a wide range of redox processes, [Ru-2(II)]<----> [(RuRuIII)-Ru-II]<----> [Ru-2(III)]<----> [(RuRuIV)-Ru-III]<----> [Ru-2(IV)], which are coupled with protonation/deprotonation at the monoatom bridge. When complex 1b was reduced with sodium amalgam, the mononuclear ruthenium(II) complex [Ru(PhCOO)(HBpz(3))(CH3CN)(2)] (4b) was isolated and characterized by spectroscopic techniques and EXAFS analysis. Upon exposure to air or dioxygen, complex 4b readily regenerated the oxo-bridged dimer 1b, and the oxo atom was confirmed to be derived from dioxygen by an isotopically-labeled experiment. The present results demonstrate the versatile redox states of diruthenium centres terminally capped by HBpz(3)(-) ligands.
  • Murafuji T, Sugimoto K, Yanagimoto S, Moriya T, Sugihara Y, Mikata Y, Kato M, Yano S
    Heterocycles 54 (2) 929 - 942 2001 [Refereed][Not invited]
  • T Funayama, M Kato, H Kosugi, M Yagi, J Higuchi, S Yamauchi
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 73 (7) 1541 - 1550 0009-2673 2000/07 [Refereed][Not invited]
     
    The lowest excited triplet (T-1) state of 3,3'-biisoquinoline(dicyano)platinum(II) [Pt(CN)(2)(i-biq)] was examined by time-resolved electron paramagnetic resonance (TREPR) and optical techniques in comparison with that of a ligand 3,3'-biisoquinoline (i-biq). Trans and cis i-biqs were assigned from obtained and calculated zero-field splittings (zfs') in the T-1 state. The zfs parameter D increased with complex formation from 2.66 to 4.66 GHz in a rigid dimethylformamide solution; the polarization pattern of the spectrum was very different between the ligand and the complex. The triplet lifetime (ca. 1 s) of i-biq is also remarkably shortened in the complex (ca. 2 ms). These facts were analyzed in terms of the spin-orbit coupling (soc) between T-1 (pi pi*) and (1,3)d pi*. From the analyses, the soc matrix element and the magnitude of delocalization of pi* electrons over the Pt atom are obtained as 65 cm(-1) and 0.02, respectively. The solvent dependences of the D value and the tripler lifetime also support the importance of the (1,3)d pi* states for the T-1 (pi pi*) properties of the complex.
  • Kato M, Kozakai M, Fukagawa C, Funayama T, Yamauchi S
    Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals 343 2000 [Refereed][Not invited]
  • Y Sugimoto, HAA Babiker, S Inanaga, M Kato, A Isogai
    PHYTOCHEMISTRY 52 (8) 1431 - 1435 0031-9422 1999/12 [Refereed][Not invited]
     
    Two oxoisoaporphine alkaloids, 2,3-dihydrodauriporphine and tyraminoporphine, together with the known alkaloid dauriporphine, were isolated from Menispermum dauricum roots cultured in a medium containing ketoconazole, a cytochrome P-450 inhibitor. Structures of the alkaloids were established by spectroscopic, crystallographic and chemical methods. (C) 1999 Elsevier Science Ltd. All rights reserved.
  • M Kato, J Takahashi
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 55 (11) 1809 - 1812 0108-2701 1999/11 [Refereed][Not invited]
     
    Two salts of (ethylenediamine-N,N')(1,10-phenanthroline-N,N') platinum(II), namely the dichloride dihydrate, [Pt(C2H8N2)(C12H8N2)]Cl-2.2H(2)O, (I), and the bis(hexafluorophosphate), [Pt(C2H8N2)(C12H8N2)] (PF6)(2), (II), have pi-phenanthroline-stacked structures. The interplanar spacings of the pi-pi stacks, however, are quite different in the two salts, being 3.38 (1) and 3.40(1) Angstrom for (I), and 3.60(5) and 3.56(5) Angstrom for (II), These are controlled by the anions located on the aliphatic sites.
  • Kato M, Kosuge C, Morii K, Sun Ahn J, Kitagawa H, Mitani T, Matsushita M, Kato T, Yano S, Kimura M
    Inorganic Chemistry 38 (7) 1638 - 1641 1999 [Refereed][Not invited]
  • A Kwon, M Kato, H Kawamura, Y Yanai, H Tokura
    EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 78 (6) 487 - 493 0301-5548 1998/11 [Refereed][Not invited]
     
    The purpose of this present study was to compare the physiological effects of the hydrophilic and hydrophobic properties of the fabrics investigated in exercising and resting subjects at an ambient temperature of 30 degrees C and a relative humidity of 50% with and without wind. Three kinds of clothing ensemble were tested: wool and cotton blend with high moisture regain (A), 100% cotton with intermediate moisture regain (B), 100% polyester clothing with low moisture regain (C). The experiments were performed using seven young adult women as subjects. They comprised six repeated periods of 10-min exercise on a cycle ergometer at an intensity of 40% maximal oxygen uptake followed by 5 min of rest (20 min for the last rest). The experiments comprised two sessions. During session I (first three repetitions of exercise and rest) the subjects were exposed to an indifferent wind velocity and during session II (last three repetitions of exercise and rest) they were exposed to a wind velocity of 1.5 m.s(-1). Rectal temperature and skin temperatures at eight sites, pulse rate and clothing microclimate were recorded throughout the whole period. The main findings can be summarized as follows: rectal temperature during session II was kept at a significantly lower level in A than in B and C. Clothing microclimate humidity at the chest was significantly lower in A than in B and C during session II. Skin and clothing microclimate temperatures at the chest were significantly lower in A than in B and C during session II. Pulse rate was significantly higher in C than in A and B during sessions I and II. It was concluded that the hydrophilic properties of the fabrics studied were of physiological significance for reducing heat strain during exercise and rest especially when influenced by wind.
  • Y Sugimoto, S Inanaga, M Kato, T Shimizu, T Hakoshima, A Isogai
    PHYTOCHEMISTRY 49 (5) 1293 - 1297 0031-9422 1998/11 [Refereed][Not invited]
     
    A novel alkaloid, dechloroacutumine, was isolated from Menispermum dauricum roots, a rich source of the chlorine-containing alkaloid acutumine, cultured in chlorine-deficient medium. Its structure was elucidated by spectral and crystallographic analysis. (C) 1998 Elsevier Science Ltd. All rights reserved.
  • Y Mikata, M Yokoyama, K Mogami, M Kato, Okura, I, M Chikira, S Yano
    INORGANICA CHIMICA ACTA 279 (1) 51 - 57 0020-1693 1998/09 [Refereed][Not invited]
     
    Three novel intercalator-linked cisplatin-type platinum complexes, cis-[PtCl2(9-(2-aminoethyl)aminomethylacridine)] (1), cis-[PtCl2(4-(2-aminoethyl) aminomethyl-2-phenylquinoline)] (2), and cis-[PtCl2(8-(2-aminoethyl)aminomethyl-2-phenylquinoline)] (3) were synthesized, The structure of 1 was determined by X-ray crystallography (triclinic, space group P (1) over bar with a=15.007(6), b=15.597(4), c = 10.398(3) Angstrom, alpha=98.51(3)degrees, beta=96.79(3)degrees, gamma = 114.61(2)degrees, Z=4, R = 0.053, R-w=0.063). The antitumor activity of the platinum complexes was investigated against the HeLa cell. Compound 3 was the most cytotoxic among the complexes synthesized here and was more effective than cisplatin. It was suggested from microscopic analysis that the acridine complex 1, which had no cytotoxicity against the HeLa cell, was not incorporated in the nucleus of the cell. Against the P388 cell, however, complex 1 gave a more therapeutic result than 3. The covalent binding ability of the cisplatin moiety was suppressed significantly in these compounds. The results of molecular mechanics showed that intercalation and covalent binding could be compatible. The cytotoxicity and DNA binding ability of phenylquinoline-type ligands were also studied to evaluate the intrinsic cytotoxicity of the intercalator. From the duplex DNA denaturation experiment and fluorescent ethidium displacement assay, the DNA binding affinities of the ligands are in agreement with the cytotoxicity of these compounds and the corresponding platinum complexes. (C) 1998 Elsevier Science S.A. All rights reserved.
  • M Kato, C Kosuge, S Yano, M Kimura
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 54 (5) 621 - 623 0108-2701 1998/05 [Refereed][Not invited]
     
    A novel platinum(II) complex, dichloro(dipyrido[3,2-a:2',3'-c]phenazine-N-4,N-5 )platinum(II), [PtCl2(C18H10N4)], forms a two-dimensional stacking structure which is constructed with both platinum-platinum and ligand pi-pi interactions in the crystal.
  • F Toda, K Tanaka, M Kato
    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 (7) 1315 - 1318 0300-922X 1998/04 [Refereed][Not invited]
     
    Photodimerisations of chalcone and its derivatives in the molten state proceed efficiently and stereoselectively to give rac-anti-head-to-head dimers in all cases tested.
  • T Tanase, T Inagaki, Y Yamada, M Kato, E Ota, M Yamazaki, M Sato, W Mori, K Yamaguchi, M Mikuriya, M Takahashi, M Takeda, Kinoshita, I, S Yano
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (4) 713 - 718 0300-9246 1998/02 [Refereed][Not invited]
     
    Reactions of Fe-III(NO3)(3) . 9H(2)O with 0.5 equivalent of 2-hydroxypropane-1.3-diamine-N,N,N',N'-tetraacetic acid (H(5)dhpta) and an excess of amino acid [glycine (Gly) or L-alanine (L-Ala)] in water with the pH adjusted to ca. 5 by a solution of NaOH gave pale green crystals formulated as Na[Fe-4(dhpta)(2)(mu-O)(mu-OH)(O2CCHRNH3)(2)] (R = H 1 or CH3 2) in moderate yields. The tetrairon(III) complexes were characterized by elemental analyses, IR and Fe-57 Mossbauer spectra, variable-temperature magnetic susceptibility, and X-ray crystallographic and absorption analyses. The structure of 2.6H(2)O was determined by X-ray crystallography to comprise a (mu-oxo)(mu-hydroxo)bis(mu-alkoxo)bis(mu-carboxylato)tetrairon(III) cluster core bridged by two dhpta and two amino acid ligands. Two identical dinuclear iron(III) units [Fe(1)Fe(2) and Fe(3)Fe(4)] are each co-ordinated by a pentadentate dhpta ligand. The Fe(1) and Fe(4) are then bridged by the carboxylate of an amino acid and an oxo group, with the Fe(2) and Fe(3) similarly linked. The central two oxo groups are protonated to form a strongly hydrogen bonded (O-H-O)(3-) bridge [O ... O 2.426(4) Angstrom]. The average Fe Fe distance for the mu-alkoxo dinuclear units is 3.692 A (intradimer) and that for the bis(mu-carboxylato)(mu-oxo/hydroxo)diiron units is 3.463 Angstrom (interdimer), both being in accord with the corresponding values from EXAFS analyses. The two L-alanine moieties are in zwitterionic form and act as interdimer bridging ligands with the carboxylate groups. The Nat counter cation is well packed between the tetrairon(III) complex anions, resulting in an infinite chain aggregation. The Fe-57 Mossbauer spectrum for 2.6H(2)O clearly demonstrated that the four iron sites are equivalent, being in a high-spin octahedral iron(III) state. The variable-temperature magnetic susceptibility measurement for 2.6H(2)O showed modest antiferromagnetism with an interdimer coupling constant (J) of -42.3 cm(-1) and an intradimer coupling constant (J') of -20.8 cm(-1).
  • S Yano, S Inoue, R Nouchi, K Mogami, Y Shinohara, Y Yasuda, M Kato, T Tanase, T Kakuchi, Y Mikata, T Suzuki, Y Yamamoto
    JOURNAL OF INORGANIC BIOCHEMISTRY 69 (1-2) 15 - 23 0162-0134 1998/02 [Refereed][Not invited]
     
    Nickel(II) complexes containing N-glycosides derived from D-glucosamine (D-GlcN) and ethylenediamine (en) and trimethylenediamine (tn), [Ni(D-GlcN-en)(2)]Cl-2.H2O (1) (D-GlcN-en = 1-{(2-aminoethyl)amino}-2-amino-1,2-dideoxy-D-glucose) and [Ni(D-GlcN-tn)(2)]Cl-2.4H(2)O (2) (D-GlcN-tn = 1-{(3-aminopropyl)amino}-2-amino-1, 2-dideoxy-D-glucose), are fairly stable in water at room temperature and showed effective antifungal activity against pathogenic yeast, Candida albicans, with the MIC (minimal concentration of inhibition) values of the complexes being 0.25 mM. The results obtained enzyme assays by using preparations of C. albicans chitinase fraction suggested that the sugar complexes 1 and 2 played a role of novel chitinase (chitin-degradation enzyme) inhibitor, where the modes of inhibition were competitive (K-i = 1.3 mM for 1, K-i = 1.8 mM for 2). The newly prepared nickel(II) complex 2 was characterized by elemental analysis, magnetic susceptibility, electronic absorption and circular dichroism spectroscopies, and an X-ray crystallographic analysis. (C) 1998 Elsevier Science Inc. All rights reserved.
  • Oh Kyung Kwon, Ae Hyun Kwon, Masako Kato, Chio Hayashi, Hiromi Tokura
    International Journal of Occupational Safety and Ergonomics 4 (1) 57 - 67 1080-3548 1998 [Refereed][Not invited]
     
    This study was designed to find the effects of two kinds of dust-free garments with (A) and without (B) frozen gel strip (FGS), and half-naked clothing (brassiere and shorts C) on thermophysiological parameters and on temperature and humidity within clothing. The heart rate, rectal, and skin temperatures as well as sweat rate and clothing microclimate were measured during 140 min in 9 healthy females. Inquiries were also made into the subjective rating of thermal, humidity, and comfort sensations. The main findings in our experiments are as follows: (a) Physiological parameters such as rectal and skin temperatures (chest and forehead), heart rate, and sweat rate were clearly lowest in garb C, intermediate in garb A, and highest in garb B throughout the experiment (b) Temperature and humidity within clothing were lower in garb A than in garb B (c) More than half of the 9 participants decreased thermal sensation by wearing garb A. These results suggest that the usage of FGS could improve the heat load in lightly working participants wearing dust-free garments. © 1998 Taylor & Francis Group, LLC. All rights reserved.
  • F Toda, K Tanaka, T Tamashima, M Kato
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 37 (19) 2724 - 2727 1433-7851 1998 [Refereed][Not invited]
  • S Yano, M Nakagoshi, A Teratani, M Kato, T Onaka, M Iida, T Tanase, Y Yamamoto, H Uekusa, Y Ohashi
    INORGANIC CHEMISTRY 36 (19) 4187 - 4194 0020-1669 1997/09 [Refereed][Not invited]
     
    Novel seven-coordinated cage-type cobalt(II) complexes containing N-glycosides from mannose-type aldoses and tris(2-aminoethyl)amine (tren), [Co((aldose)(3)tren)]X-2.nH(2)O (1a.5H(2)O, aldose=D-mannose (D-Man), X = Cl-; 1b.5H(2)O, aldose = 6-deoxy-L-mannose (L-Rha), X = Cl-; 2a.4H(2)O, aldose = D-Man, X = Br-; 2b.H2O, aldose = L-Rha, X = Br-) and [Co((aldose)(3)tren)]SO4.nH(2)O (3a.4H(2)O, aldose = D-Man; 3b.3H(2)O, aldose = L-Rha), where (aldose)(3)tren is tris(2-(aldosylamino)ethyl)amine, were prepared and characterized by elemental analysis, electronic absorption and circular dichroism spectroscopies, and X-ray crystallography. Crystal data are as follows. 2b.2CH(3)OH: C26H56N4O14Br2Co, monoclinic, space group P2(1), a=11.045(2) Angstrom, b=17.283(6) Angstrom, c=10.996(3) Angstrom, beta=117.371(6)degrees, V=1864(1) Angstrom(3), Z=2, R=0.072 for 2787 independent reflections. 3b.3H(2)O.CH3OH:C25H58N4O20SCo, orthorhombic, space group P2(1)2(1)2(1), a=14.836(2) Angstrom, b=22.489(2) Angstrom, c=12.181(3) Angstrom, V=4064(1) Angstrom(3), Z=4, R=0.077 for 2010 independent reflections. The complex cation of 2b consists of a cobalt atom coordinated by a heptadentate (L-Rha)(3)tren ligand to produce a mono-face-capped octahedron having pseudo-C-3 symmetry with-a Lambda (lambda(3)-ob form) configuration around the metal. The complex cation of 3b has a monoface-capped octahedron coordinated by a heptadentate (L-Rha)(3)tren ligand having pseudo-C-3 symmetry with a Delta (lambda(3)-lel form) configuration. The other facial site of the complex cation is capped by the SO42- anion through hydrogen banding with the hydroxy groups of L-rhamnose residues. The C-3 helical-configurational inversion around the cobalt(II) center, Delta < -- > Lambda, induced by an interaction between the sugars and the SO42- anion, was monitored by circular dichroism spectroscopy, for which the sign of the Cotton effect of 1 and 2, having halide counteranions, is opposite to that of 3, having sulfate counteranions, and was found to proceed reversibly upon addition and removal of sulfate anions. The intensities of circular dichroism spectra for [Co((L-Rha)(3)tren)](2+) and [Co((D-Man)(3)tren)](2+) were appreciably changed upon addition of sulfate ions. The spectral changes were interpreted in terms of ion-pair formation. On the basis of electrostatic theories of ion association, the closest distance between the sulfate ion and the [Co((D-Man or L-Rha)(3)tren)](2+) cation was estimated as similar to 5 Angstrom, which is consistent with the Co-S distance of 4.697(6) Angstrom observed in the crystal structure of 3b. The sulfate ion was suggested to fit into the cavity composed of the sugar hydroxyl groups through hydrogen bonds even in the solution state.
  • M Kato, C Kosuge, S Yano, M Kimura
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 53 (7) 838 - 840 0108-2701 1997/07 [Refereed][Not invited]
     
    The crystal structure of (2,2'-bipyridine-N,N')(ethylenediamine-N,N')platinum(II) bis(hexafluoraphosphate), [Pt(C2H8N2)(C10H8N2)](PF6)2, [Pt(bpy)(en)](PF6)(2), contains pi-bpy-stacked columns of platinum complex cations, The bpy ligands are stacked keeping van der Waals contacts although the crystal exhibits essentially the same (3) pi-pi* emission spectrum as that in dilute solution.
  • Y Mikata, K Mogami, M Kato, Okura, I, SB Yano
    BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 7 (8) 1083 - 1086 0960-894X 1997/04 [Refereed][Not invited]
     
    A cisplatin-type complex tethered to acridine intercalator via one methylene chain has been synthesized. Its structure was elucidated by X-ray crystallography. A permeability into cell, interaction with calf thymus DNA (ct-DNA), and antitumor activity against HeLa and P388 cells were studied. (C) 1997 Elsevier Science Ltd.
  • Kato M, Ha M, Tokura H
    Journal of human ergology 26 (1) 51 - 59 1997 [Refereed][Not invited]
  • K Tsukahara, J Kaneko, T Miyaji, T Hara, M Kato, M Kimura
    CHEMISTRY LETTERS (5) 455 - 456 0366-7022 1997 [Refereed][Not invited]
     
    Stereoselectivity was found in the intracomplex quenching process between the excited triplet state of Delta-tris(2,2'-bipyridine)ruthenium(II) and optically active viologen containing naphthyl group(s), where the bipyridine ligand interacts with the naphthyl group of viologen.
  • T Tanase, Y Yamada, K Tanaka, T Miyazu, M Kato, K Lee, Y Sugihara, W Mori, A Ichimura, Kinoshita, I, Y Yamamoto, M Haga, Y Sasaki, S Yano
    INORGANIC CHEMISTRY 35 (21) 6230 - 6239 0020-1669 1996/10 [Refereed][Not invited]
     
    [RuCl2(dmso)(4)] (dmso = dimethyl sulfoxide) was treated with dhptaH(5) (1,3-diamino-2-hydroxypropanetetraacetic acid) and carboxylate ligands in the presence of NaOH or KOH and gave dinuclear ruthenium(III) complexes of dhpta with two bridging carboxylates, M[Ru(dhpta)(mu-O(2)CR)(2)] (1, R = C6H5, M = Na; 1', R = C6H5, M = K; 2, R = p-OHC6H4, M = Na; 3, R = p-NH2C6H4, M = Na; 4, R = CH3, M = Na; 4', R = CH3, M = K), which were characterized by elemental analysis, mass, electronic absorption, and H-1 and C-13 NMR spectroscopies, and X-ray absorption and crystallographic analyses (4, orthorhombic, space group Pca2(1) with a = 21.359(4) Angstrom, b = 7.484(2) Angstrom, c = 12.930(2) Angstrom, Z = 4, R = 0.065, and R(w) = 0.044 for 1116 independent reflections with I > 3 sigma(I); 4'. 1.5H(2)O: monoclinic, P2(1), a = 7.689(2) Angstrom, b = 17.213(2) Angstrom, c = 18.103(2) Angstrom, beta = 94.50(1)degrees, Z = 4; R = 0.041, and R(w) = 0.047 for 4705 independent reflections with I > 3 sigma(I)). The complex anion consists of two ruthenium atoms bridged by the alkoxide of dhpta and the two acetate ligands. The Ru-Ru distances of 3.433(3) Angstrom (4) and 3.421(1) Angstrom (average) (4') are longer than those found in (mu-oxo)bis(mu-carboxylato)diruthenium(III) complexes. EXAFS analysis and H-1 NMR spectra indicated that complexes 1-4 have the identical dinuclear structure in both solid and water solution states. Temperature-dependent magnetic susceptibility of 1-4 showed a strong antiferromagnetic interaction between the two Ru(III) ions with -J = 310-470 cm(-1). Cyclic voltammograms showed two reduction processes at ca. -0.34 and ca. -0.94 V vs Ag/AgCl, corresponding to two stepwise one-electron reductions, (RuRuIII)-Ru-III <-> (RuRuII)-Ru-III <-> (RuRuII)-Ru-II. The most remarkable feature is the large separation between the two redox potentials, implying that the mixed-valence diruthenium(III,II) complexes of dhpta are fairly stable. Potentiostatic electrolysis of 1-4 at a potential in between E(1/2)(1) and E(1/2)(2) consumed 1 F per dimer and afforded a mixed-valence diruthenium species, [(RuRuIII)-Ru-II(dhpta)mu-O(2)CR)(2)](2-), in solution, which showed two weak and broad absorption bands (nu(max) 5.5-5.7 and 11.6-11.9 kcm(-1)) in DMF assignable to intervalence charge transfer (IT) bands. The lower energy IT band was analyzed by Gaussian curve fitting and the electron exchange integral H-ad was estimated as 640-870 cm(-1) on the basis of Hush's theory. The spectroscopic analysis indicated that [(RuRuIII)-Ru-II(dhpta)(O(2)CR)(2)](2-) belongs to Class II type mixed-valence diruthenium complexes.
  • Y Sugihara, K Takakura, T Murafuji, R Miyatake, K Nakasuji, M Kato, S Yano
    JOURNAL OF ORGANIC CHEMISTRY 61 (20) 6829 - 6834 0022-3263 1996/10 [Refereed][Not invited]
     
    3-(Diethylboryl)pyridine (1a), a versatile starting material for the preparation of arylpyridines, is notable for its stability under ambient conditions, in spite of little steric hindrance on the boron atom. H-1 and C-13 spectra of 1a indicated that the boryl group does not act as a mere pi-acceptor and that the boron atom is shielded by ca. 50 ppm even when compared with trivalent boron atoms conjugated with the pi-donor. A single-crystal X-ray crystallographic study for la revealed formation of a cyclic-tetramer with a void via the intermolecular boron-nitrogen coordination bond. Vapor pressure osmometry in various solvents suggested that la comprises the tetramer in these solutions. In order to know the actual structure, synthesis of 3-(2-methoxyethoxy)-5-(diethylboryl)pyridine (1b) and its scrambling experiment with 1a were carried out. Heating at 100 degrees C for 24 h was required to attain the equilibrium of the scrambling of the component molecules in the tetramers. This means that 3-(diethylboryl)pyridines 1a and 1b comprise the rigid cyclic-tetramer in solution at ambient temperature. Compound 1b is stable in aerated tetrahydrofuran containing up to 33 % water.
  • T Tanase, M Doi, R Nouchi, M Kato, Y Sato, K Ishida, K Kobayashi, T Sakurai, Y Yamamoto, S Yano
    INORGANIC CHEMISTRY 35 (17) 4848 - 4857 0020-1669 1996/08 [Refereed][Not invited]
     
    Reactions of [Ni(tren)(H2O)(2)]X(2) (tren = tris(2-aminoethyl)amine; X = Cl (1a), Br (1b); X(2) = SO4 (1c)) with mannose-type aldoses, having a 2,3-cis configuration (D-mannose and L-rhamnose), afforded {bis(N-aldosyl-2- aminoethyl) (2-aminoethyl)amine}nickel(II) complexes, [Ni(N,N'-(aldosyl)(2)-tren)]X(2) (aldosyl = D-mannosyl, X = Cl (2a), Br (2b), X(2) = SO4 (2c); aldosyl = L-rhamnosyl, X(2) = SO4 (3c)). The structure of 1c was confirmed by X-ray crystallography to be a mononuclear [(NiN4O2)-N-III] complex with the tren acting as a tetradentate ligand (1c . 2H(2)O: orthorhombic, Pbca, a = 15.988(2) Angstrom, b = 18.826(4) Angstrom, c = 10.359(4) Angstrom, V = 3118 Angstrom(3), Z = 8, R = 0.047, and R(w) = 0.042). Complexes 2a,c and 3c were characterized by X-ray analyses to have a mononuclear octahedral Ni(II) structure ligated by a hexadentate N-glycoside ligand, bis(N-aldosyl-2-aminoethyl) (2-aminoethyl)amine (2a . CH3OH: orthorhombic, P2(1)2(1)2(1), a = 16.005(3) Angstrom, b = 20.095(4) Angstrom, c = 8.361(1) Angstrom, V = 2689 Angstrom(3), Z = 4, R = 0.040, and R(w) = 0.027. 2c . 3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.93(2) Angstrom, b = 21.823(8) Angstrom, c = 9.746(2) Angstrom, V = 3176 Angstrom(3), Z = 4, R = 0.075, and R(w) = 0.080. 3c . 3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.560(4) Angstrom, b = 21.694(5) Angstrom, c = 9.786(2) Angstrom, V = 3091 Angstrom(3), Z = 4, R = 0.072, and R(w) = 0.079). The sugar part of the complex involves novel intramolecular sugar-sugar hydrogen bondings around the metal center. The similar reaction with D-glucose, D-glucosamine, and D-galactosamine, having a 2,3-trans configuration, resulted in the formation of a mono(sugar) complex, [Ni(N-(aldosyl)-tren)(H2O)(2)]Cl-2 (aldosyl = D-glucosyl (4b), 2-amino-2-deoxy-D-glucosyl (5a), and 2-amino-2-deoxy-D-galactosyl (5b)), instead of a bis(sugar) complex. The hydrogen bondings between the sugar moieties as observed in 2 and 3 should be responsible for the assembly of two sugar molecules on the metal center. Reactions of tris(N-aldosyl-2-aminoethyl)amine with nickel(II) salts gave the tris(sugar) complexes, [Ni(N,N',N''-(aldosyl)(3)-tren)]X(2) (aldosyl = D-mannosyl, X = Cl (6a), Br (6b); L-rhamnosyl, X = Cl (7a), Br (7b); D-glucosyl, X = Cl (9); maltosyl, X = Br (10); and melibiosyl, X = Br (11)), which were assumed to have a shuttle-type C-3 symmetrical structure with Delta helical configuration for D-type aldoses on the basis of circular dichroism and C-13 NMR spectra. When tris(N-rhamnosyl)-tren was reacted with NiSO4 . 6H(2)O at low temperature, a labile neutral complex, [Ni(N,N',N''-(L-rhamnosyl)(3)-tren)(SO4)] (8), was successfully isolated and characterized by X-ray crystallography, in which three sugar moieties are anchored only at the N atom of the C-1 position (8 . 3CH(3)OH . H2O: orthorhombic, P2(1)2(1)2(1), a = 16.035(4) Angstrom, b = 16.670(7) Angstrom, c = 15.38(1) Angstrom, V = 4111 Angstrom(3), Z = 4, R = 0.084, and R(w) = 0.068). Complex 8 could be regarded as an intermediate species toward the C-3 symmetrical tris(sugar) complexes 7, and in fact, it was readily transformed to 7b by an action of BaBr2.
  • Yano S, Doi M, Kato M, Okura I, Nagano T, Yamamoto Y, Tanase T
    Inorganica Chimica Acta 249 (1) 1 - 3 1996 [Refereed][Not invited]
  • S Yano, M Nakagoshi, A Teratani, M Kato, T Tanase, Y Yamamoto, H Uekusa, Y Ohashi
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 276 253 - 256 1058-725X 1996 [Refereed][Not invited]
     
    The structure of [Co((Rha)(3)-tren)]Br-2.2CH(3)OH, where (Rha)3-tren is tris (N-rhamnosyl-2-aminoethyl)amine, was elucidated by X-ray crystallography, which confirmed the unprecedented configurational inversion of [Co((Rha)(3)-tren)](2+), around the metal center reversibly by an addition and a removal of sulfate.
  • M Kato, K Sasano, C Kosuge, M Yamazaki, S Yano, M Kimura
    INORGANIC CHEMISTRY 35 (1) 116 - 123 0020-1669 1996/01 [Refereed][Not invited]
     
    Three new platinum complexes containing 3,3'-biisoquinoline (i-biq), [Pt(CN)(2)(i-biq)] (1), [PtCl2(i-biq)] (2), and [Pt(i-biq)(2)](PF6)(2) (3), have been synthesized as orange-red, yellow, and colorless crystals, respectively. Their crystal structures and luminescence properties are reported. Crystal data: for 1.0.5H(2)O, PtO0.5N4C20H13, orthorhombic, Pbcm, a = 13,989(2) Angstrom, b = 18.304(1) Angstrom, c = 6.682(3) Angstrom, V = 1710.9(6) Angstrom(3), Z = 4, and final R = 0.039 (R(w) = 0.033) for 970 independent reflections; for 2.DMF.H2O, PtCl2O2N3C21H21, triclinic, P (1) over bar, a = 11.047(1) Angstrom, b = 12.397(3) Angstrom, c = 8.000(2) Angstrom, alpha = 106.55(1)degrees, beta = 100.15(1)degrees, gamma = 76.15(1)degrees, V = 1012.8(3) Angstrom(3), Z= 2, and final R = 0.058 (R(w) = 0.077) for 4219 independent reflections; for 3.2DMF, PtP2F12O2N6C42H38, triclinic, P (1) over bar, a = 10.795(2) Angstrom, b = 13.511(2) Angstrom c = 8.281(1) Angstrom, alpha = 105.22(1)degrees, beta = 112.17(1)degrees, gamma = 85.02(1)degrees, V = 1079.2(3) Angstrom(3), Z = 1, and final R = 0.038 (R(w) = 0.042) for 3606 independent reflections. Square-planar complexes of 1 are stacked in the crystal to form a columnar structure with the Pt-Pt distance of 3.34 Angstrom. The crystal emits strongly, even at room temperature, and the emission spectrum is similar to that for the [Pt(CN)(2)-(bpy)] crystal (bpy = 2,2'-bipyridine), which is due to a (3)d pi*[d sigma*(Pt) --> pi*(i-biq)] transition. The single crystal emission spectrum at 77 K is, however, observed as a superposition of broad (3)d pi* and sharp (3) pi pi*(i-biq) emissions. The crystal structure of 2 has a completely different stacking structure from that of 1. The stacking occurs on the i-biq ligands, and the Pt atoms are separated more than 6 Angstrom. The complex exhibits only a structured emission component assigned to the 3 pi pi*(i-biq) transition in the crystal at 77 K, in agreement with the crystal structure with no Pt-Pt interaction. In the crystal of 3, the [Pt(i-biq)(2)](2+) complexes are stacked but offset, being in close contact between parts of adjacent i-biq ligands. There is no Pt-Pt interaction also in this case. Two i-biq ligands in the complex are distorted to adopt the bowed conformation due to the steric crowding of the a-hydrogens on opposite ligands. Nevertheless, 3 provides almost the same (3) pi pi* emission spectrum as 1 and 2 in dilute glassy solution at 77 K. The (3) pi pi* emission spectra observed in the crystals of these Pt(II) complexes are red-shifted compared with those in dilute glassy solution. The fact is attributable to the pi-pi intermolecular interactions between the ligands in the crystals. The factors controlling the crystal structures for these complexes are also discussed.
  • Tanaka K, Ichimura A, Kinoshita I, Haga M.-A, Mori W, Kato M, Yano S
    Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals 285-286 127 - 132 1996 [Refereed][Not invited]
  • S Yano, T Inagaki, Y Yamada, M Kato, M Yamasaki, K Sakai, T Tsubomura, M Sato, W Mori, K Yamaguchi, Kinoshita, I
    CHEMISTRY LETTERS (1) 61 - 62 0366-7022 1996 [Refereed][Not invited]
     
    The reaction of L-alanine (L-ala) with Fe(NO3)(2) . 9H(2)O in the presence of H(5)dhpta (1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid) and base (NaOH) affords the novel tetranuclear complex Na[Fe-4(dhpta)(2)(O)(OH)(L-ala)(2)]. 6H(2)O having L-alaninato bridges and an (Fe-4(O2H))(9+) core whose crystal structure and magnetic properties were determined.
  • S YANO, S INOUE, R NOUCHI, M KATO, T SUZUKI
    BIOLOGICAL & PHARMACEUTICAL BULLETIN 18 (6) 923 - 925 0918-6158 1995/06 [Refereed][Not invited]
     
    A nickel(II) complex containing N-glycosides derived from the reaction of D-glucosamine (D-GlcN) and ethylenediamine (en) [Ni(D-GlcN-en)(2)]Cl-2 . H2O showed effective antifungal activity against pathogenic yeast, Candida albicans, where the MIC (minimal concentration of inhibition) value of the complex is 0.25 mM.
  • M KATO, Y YAMADA, T INAGAKI, W MORI, K SAKAI, T TSUBOMURA, M SATO, S YANO
    INORGANIC CHEMISTRY 34 (10) 2645 - 2651 0020-1669 1995/05 [Refereed][Not invited]
     
    A series of diiron(III) complexes containing alkoxo and carboxylato bridges, [Fe-2(dhpta)(OOCR)(H2O)(2)] (H-5-dhpta = 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid; R = C6H4OH (1), CH2CH=CH2 (2), C6H4-NH2 (3), CH2CH2Br (4); CH=CHCH3 (5)) have been synthesized. Their molecular structures and magnetic properties were investigated. For 1 and 2, the crystal structures have been determined by X-ray analysis. Crystal data: for 1, dihydrate, triclinic, P $($) over bar$$ 1, a = 9.929(3) Angstrom, b = 18.955(6) Angstrom, c = 7.862(2) Angstrom, alpha = 113.60(2)degrees, beta = 107.57(2)degrees, gamma = 61.79(3)degrees, V = 1182.2(7) Angstrom(3), Z = 2, R = 0.050; for 2, triclinic, P $($) over bar$$ 1, a = 10.020(1) Angstrom, b = 15.952(1) Angstrom, c = 6.7523(7) Angstrom, alpha = 95.536(7)degrees, beta = 97.968(8)degrees, gamma = 86.612(7)degrees, V = 1062.7(2) Angstrom(3), Z = 2, R = 0.050. For both complexes, two Fe(III) ions take rather distorted octahedral structure and are bridged by the alkoxyl group of dhpta and the carboxylate ion. Fe-O(R) distances are 2.006(2) and 1.985(2) Angstrom for 1 and 1.971(4) and 1.998(3) Angstrom for 2, and the Fe-O(R)-Fe angle is 130.0(1)degrees for 1 and 130.2(2)degrees for 2. EXAFS, XANES, and IR data support that all the complexes have similar (mu-alkoxo)(mu-carboxylato)diiron dimer structures. Independent of the bridging carboxylate ligand, all these complexes exhibit similar weak antiferromagnetic exchange interactions between the spins of the ferric ions through the O(-R) bridge (-J = 14-16 cm(-1)). Among these complexes, a small but significant increase in the -J value with shorter Fe-(mu-O) distance is noted. This indicates that the spin exchange interaction is very sensitive to the bond length between Fe and bridging oxygen atoms also for the (mu-alkoxo)diiron(III) complexes. Both 1 and 2 have the crystal structures with a separate arrangement of hydrophilic and hydrophobic parts and stacking of the pi system.
  • Kato M, Ando T, Yamashita Y, Tokura H
    Applied human science : journal of physiological anthropology 14 (3) 119 - 124 1995 [Refereed][Not invited]
  • S YANO, M KATO, K TSUKAHARA, M SATO, T SHIBAHARA, K LEE, Y SUGIHARA, M IIDA, K GOTO, S AOKI, Y SHIBAHARA, H NAKAHARA, S YANAGISAWA, H MIYAGAWA
    INORGANIC CHEMISTRY 33 (22) 5030 - 5035 0020-1669 1994/10 [Refereed][Not invited]
     
    The noncoordinated hydroxyl group of [Co(dhpta)](-) (where dhpta = 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetate ion) was O-acylated by reaction with a series of acid anhydrides (acetic anhydride, n-valeric anhydride, benzoic anhydride, phthalic anhydride, succinic anhydride, octanoic anhydride, and dodecanoic anhydride) in the presence of 4-(dimethylamino)pyridine, after the potassium salt of the complex was dissolved in acetonitrile by using cryptand 222. Fairly high yields under remarkably mild conditions were achieved without altering the coordination sphere. The esterified complexes were characterized by elemental analysis, electronic absorption and NMR spectroscopies, and X-ray crystallography. X-ray crystal structure determinations of (DMAP-H)[Co-(Ben-dhpta)] (10) and (STC-H)[Co(Val-dhpta)].6H(2)O (11) are reported, where DMAP-H, Ben-dhpta, STC-H, and Val-dhpta represent 4-(dimethylamino)pyridinium cation, O-benzoylated dhpta, strychnine cation, and O-valerylated dhpta, respectively. Crystal data for 10: formula C25H29N4O10Co, space group P2(1)2(1)2(1) (orthorhombic); a = 12.5709 (9) Angstrom, b = 25.338 (3) Angstrom, c = 8.0707 (6) Angstrom, Z = 4, R = 0.1034. Crystal data for 11: formula C37H57N4O18Co, space group P2(1) (monoclinic); a = 19.498 (10) Angstrom, b = 11.625 (5) Angstrom, c = 9.038 (2) Angstrom, beta = 95.33 (3)degrees, Z = 2, R = 0.072. In both complexes, the cobalt is octahedrally coordinated with a hexadentate dhpta unit. The oxygen atom of the noncoordinated hydroxyl group of dhpta binds to the carboxylic carbon atom of each acid residue to form an ester bond. Measurements of cobalt-59 NMR for the aqueous solutions of the cobalt(III) complexes having a long alkyl (octyl and dodecanoyl) chain ligand indicated the formation of ion-aggregates above cmc (critical micelle concentration), which was determined from the surface tension.
  • M KATO, T SASAGAWA, Y ISHIHARA, S YAMADA, S FUJITANI, M KIMURA
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (4) 583 - 587 0300-9246 1994/02 [Refereed][Not invited]
     
    The photosensitized decomposition of [Co(ox)3]3- (H-2ox = oxalic acid) and [Co(acac)3] (Hacac = acetylacetone) proceeded,stereoselectively in the presence of optically active [Ru(biPY)3]2+ (bipy = 2,2'-bipyridine). Homochiral (DELTA-DELTA or LAMBDA-LAMBDA) preference for [Co(ox)3]3- contrary to heterochiral (DELTA-LAMBDA) preference for [Co(acac)3] was found in aqueous solution according to the circular dichroism appearing upon decomposition of the racemic complex, and by the decomposition rate of each optical isomer. For the [Co(ox)3]3- complex the selectivity varied with the addition of an organic solvent such as methanol and acetonitrile following a decrease in the decomposition rate. The factors resulting in the different stereoselectivity between the similar tris-chelate complexes containing planar bidentate ligands have been investigated. Quenching rate constants for DELTA-*[Ru(bipy)3]2+ obtained from emission lifetimes demonstrated the homochiral preference in the quenching process with both [Co(ox)3]3- and [Co(acac)3] in aqueous solution. Chromatographic experiments using a SP-sephadex C-25 column exchanged with DELTA-[Ru(bipy)3]2+ demonstrated the higher stability of the DELTA-DELTA compared with the DELTA-LAMBDA pair. It is concluded that overall selectivity is controlled by the relative and competitive rates between the back electron transfer and decomposition processes.
  • Bouchet F, Fujisawa H, Kato M, Yamaguchi T
    Studies in Surface Science and Catalysis 84 (C) 2029 - 2036 1994 [Refereed][Not invited]
  • Tanase T, Nakagoshi M, Teratani A, Kato M, Yamamoto Y, Yano S
    Inorganic Chemistry 33 (1) 5 - 6 1994 [Refereed][Not invited]
  • T TANASE, R NOUCHI, Y OKA, M KATO, N NAKAMURA, T YAMAMURA, Y YAMAMOTO, S YANO
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (17) 2645 - 2652 0300-9246 1993/09 [Refereed][Not invited]
     
    The reaction of [Ni(tn)3]2+ ions (tn = 1,3-diaminopropane) with disaccharides having a glucose reducing terminal, i.e. maltose, lactose, cellobiose, and melibiose, in the presence of a catalytic amount of ammonium chloride gave blue, Paramagnetic bis(N-D-aldosylpropane-1,3-diamine)nickel(II) complexes. The complexes were characterized by elemental analysis, magnetic susceptibilities, electronic absorption and circular dichroism spectroscopies, X-ray absorption and crystallographic analyses. The complex bis[N-(4-O-alpha-D-glucopyranosylglucosyl)propane-1,3-diamine]nickel(II) bromide dihydrate crystallizes in the hexagonal space group P6(4)22, with a = 22.125(8), c = 21.464(9) angstrom, and Z = 6. The structure was solved by Patterson methods and refined by full-matrix least-squares techniques to R = 0.080 and R' = 0.094. The complex cation has C2 symmetry and the central nickel atom is octahedrally coordinated by two tridentate glycosylamine ligands formed from maltose and tn. Each ligand is bonded through the oxygen atom of the hydroxyl group at C2 of maltose and through the two nitrogen atoms of the diamine in a meridional mode. The co-ordination behaviour of the glucose unit in the octahedral nickel(II) complexes has been established. In the crystal packing, the complex cation exists in a novel dimeric form supported by intermolecular hydrogen bonds, which might provide some fundamental information concerning sugar-sugar interactions in biological systems.
  • S YANO, M KATO, H SHIOI, T TAKAHASHI, T TSUBOMURA, K TORIUMI, T ITO, M HIDAI, S YOSHIKAWA
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (11) 1699 - 1706 0300-9246 1993/06 [Refereed][Not invited]
     
    Some natural aldohexoses reacted with [Ni(tn)3]2+ (tn = trimethylenediamine) to yield octahedral nickel(II) complexes containing glycosylamine ligands. The complexes were characterized by elemental analyses, magnetic moments, electronic and CD spectra. The molecular structure of [Ni(L-Rha-tn)2]Br2.2H2O.MeOH [L-Rha-tn = 1-(3-aminopropylamino)-1,6-dideoxy-L-mannose] 1 has been determined by single-crystal X-ray techniques: orthorhombic, space group P2(1)2(1)2(1), a = 12.373(l), b = 21.614(2), c = 11.272(1) angstrom, least-squares refinement led to a final R factor of 0.044 using 2657 reflections having F(o) > 3sigma(F(o)). From X-ray crystallographic studies of glycosylamine complexes, two typical co-ordination structures of the aldose unit have been found in 1 and [Ni(D-GlcN-en)2]2+ [D-GlcN-en = 2-amino-1-(2-aminoethylamino)-1,2-dideoxy-D-glucose], which can be discriminated by the two geometrical isomeric forms arising from the two substituents on C1 and C2 of the pyranoside ring, namely cis and trans. The sugar unit of 1 has cis geometry containing equatorial and axial substituents on C1 and C2 of the pyranoside ring. In contrast, the sugar unit of the D-GlcN-en complex has trans geometry at these positions, which are both equatorial. Assuming the C-4(1) (chair) conformers to be the most stable and based on some stereochemical considerations of both the sugars and the chelate rings, the structures of the sugar units in the glycosylamine complexes from all natural aldohexoses can be classified into either of the above two types, the only difference being the relative absolute configuration at C2 and C5. This classification is well correlated with the CD spectral patterns obtained in methanolic solutions.
  • T KOJIMA, T USUI, A SHIMADA, M YASHIRO, T TANASE, R YOSHIOKA, R KURODA, S YANO, M HIDAI, M KATO, K KOBAYASHI, T SAKURAI, S YOSHIKAWA
    INORGANIC CHEMISTRY 30 (24) 4535 - 4541 0020-1669 1991/11 [Refereed][Not invited]
     
    The reaction of alpha-aminomalonate (AM2-) with trans-[CoCl2(2,3,2-tet)]ClO4 (2,3,2-tet = 1,9-diamino-3,7-diazanonane) (1) in MeOH in the presence of Et3N under aerobic conditions gave an AM2- complex (2), unusually stabilized alpha-diamine complexes (3, 4), and a carbinolamine complex (5). The X-ray crystallographic study was undertaken on [Co(AM)(2,3,2-tet)]ClO4.H2O (2) and the alpha-diamine complexes [Co(N-(2-aminoethyl)-N-(6-amino-4-azahexyl)-alpha,alpha-diaminomalonato)]ClO4 (3) and [Co(N-(9-amino-3,7-diazanonyl)-alpha,alpha-diaminomalonato)]ClO4.H2O (4), and the following data were obtained. For compound 2: C10-H23N5O4CoClO4.H2O, monoclinic, space group Cc, a = 13.856 (2) angstrom, b = 11.466 (2) angstrom, c = 11.898 (3) angstrom, beta = 107.32 (1)-degrees, Z = 4, R = 0.057, R(w) = 0.066. For compound 3: C10H21N5O4CoClO4, monoclinic, space group P2(1)/c, a = 7.399 (5) angstrom, b = 23.199 (5) angstrom, c = 9.452 (4) angstrom, beta = 92.02 (5)-degrees, Z = 4, R = 0.050, R(w) = 0.052. For compound 4: C10H21N5O4CoClO4.H2O, space group P2(1)/c, a = 7.360 (2) angstrom, b = 13.571 (3) angstrom, c = 17.370 (6) angstrom, beta = 91.02 (2)-degrees, Z = 4, R = 0.067, R(w) = 0.070. The C-N bond formation between AM2- and the amine ligand was promoted by dioxygen, Co(III) ion, heat, and MeOH and was enhanced photoinductively. The carbinolamine complex 5 was also obtained from the reaction of ketomalonate anion (KM2-) with 1 in MeOH in the presence of NEt3. X-ray crystallographic study on the carbinolamine complex, [Co(N-(9-amino-3,7-diazanonyl)-alpha-amino-alpha-hydroxylmalonato)]ClO4.H2O (5) was also performed: C10H20N4O5CoClO4.H2O, orthorhombic, space group P2(1)2(1)2(1), a = 7.291 (1) angstrom, b = 13.408 (2) angstrom, c = 17.143 (3) angstrom, Z = 4, R = 0.061, R(w) = 0.066. The results of X-ray crystallography and pK(a) measurements indicated that the uncoordinated NH2 or OH groups of 3, 4, and 5 had some properties which were similar to those of an anilinic amino group or a phenolic hydroxy group in spite of being bound to the sp3 carbon atoms.
  • M KATO, S YAMAUCHI, N HIROTA
    CHEMICAL PHYSICS LETTERS 157 (6) 543 - 546 0009-2614 1989/05 [Refereed][Not invited]
  • M KATO, S YAMAUCHI, N HIROTA
    JOURNAL OF PHYSICAL CHEMISTRY 93 (9) 3422 - 3425 0022-3654 1989/05 [Refereed][Not invited]

Books etc

  • ハウスクロフト無機化学(上・下)
    (Joint translation)
    東京化学同人 2012
  • フォトクロミズムの新展開と光メカニカル機能材料
    "シーエムシー出版 2011
  • New Frontiers in Photochromism and Photomechanical Materials
    2011
  • 有機半導体デバイス―基礎から最先端材料・デバイスまで―
    オーム社 2010
  • 配位空間の化学-最新技術と応用-「蒸気応答性発光材料」
    シーエムシー出版 2009
  • Miscellaneous Examples of Photochromic Complexes and Luminescence Chromism
    (pp.274-288)
    Kodansha/Springer 2007
  • Inorganic Chromotropism
    Kodansha/Springer 2007
  • 金属錯体の光化学 -発光素子および発光センサー-
    (Joint work)
    三共出版株式会社 2007
  • Crystal Structures and Functionalities of Platinum(II) Complexes Controlled by Various Intermolecular Interactions
    (Vol. 25, pp 351-373)
    New Jersey 2006
  • 関 隆広監修,「新規クロミック材料の設計・機能・応用」
    シーエムシー出版 2005
  • 4. 日本化学会編,「第5版実験化学講座 22金属錯体遷移金属クラスター」
    丸善 2004
  • プロフェッショナル英和辞典SPED TERRA(物質・工学編)
    小学館 2004
  • 3. 日本化学会近畿支部編, 「もっと化学を楽しくする5分間」
    化学同人 2003
  • 日本化学会編,「化学者のための基礎講座12 X線構造解析」
    朝倉書店 1999
  • 基礎錯体工学研究会編,「錯体化学-基礎と最新の話題」
    講談社サイエンティフィック 1994

Conference Activities & Talks

  • apor and Mechanically Induced Chromic Behaviour of Platinum Complexes with a Dimer-of-dimer Motif and the Effects of Hetero Metal Ions  [Invited]
    KATO Masako
    The 2nd Japan-France Coordination Chemistry Symposium  2013/11
  • Chromic Metal Complexes with Photofunctionality  [Invited]
    KATO Masako
    4th Asian Conference on Coordination Chemistry  2013/11
  • Construction of photochemical hydrogen evolution systems based on the effective utilization of 3d metals  [Invited]
    KATO Masako
    The 9th Nanjing-Hokkaido-NIMS/MANA Joint Symposium  2013/10
  • Chromic Metal Complexes with Photofunctionality  [Invited]
    KATO Masako
    International Symposium for the 70th Anniversary of the Tohoku Branch of the Chemical Society of Japan,  2013/09
  • KATO Masako
    The 5th International Conference of the OCU Advanced Research Institute for Natural Science and Technology (OCARINA)  2013/03  Osaka,Japan
  • 発光性クロミック金属錯体  [Invited]
    東北大学大学院理学研究科化学専攻錯体化学研究室招待講演  2013/02
  • 光機能性金属錯体の開拓-その可能性と魅力  [Invited]
    加藤 昌子
    平成24年度「るつぼ」セミナー  2013/01
  • 発光性クロミック金属錯体  [Invited]
    山形大学理学部生命物質化学科招待講演  2012/12
  • Luminescence Properties and Photochromic Response of Cyclometalated Dinuclear Platinum Complexes  [Invited]
    KATO Masako
    2012 HU-NU-SNU-NIMS/MANA Joint Symposium,  2012/12
  • “Luminescence Properties and Photochromic Response of Cyclometalated Dinuclear Platinum Complexes”  [Invited]
    KATO Masako
    Cambodian Malaysian Chemical Conference (CMCC)  2012/10
  • 動的構造秩序に基づく発光性クロミック金属錯体の構築  [Invited]
    第4回北海道大学・KEK 連携シンポジウム  2012/10
  • Vapochromic luminescence of platinum complexes based on the linkage isomerization  [Invited]
    KATO Masako
    Polish-Japanese Seminar  2012/09
  • 環境感応型発光性金属錯体の新展開  [Invited]
    日本化学会第92春季年会  2012/03
  • 元素戦略に基づく3d金属錯体光水素発生系の構築  [Invited]
    平成23年度大阪市立大学複合先端研究機構年次総会  2012/03
  • Photodimerization and Clusterization of Metal-Hydrazone Complexes Accompanied by Covalent Bond Formation  [Invited]
    KATO Masako
    3rd Asian Conference on Coordination Chemistry (ACCC-3)  2011/10
  • 金属錯体の複合・集積化による新しい光機能性  [Invited]
    第108回触媒討論会  2011/09
  • Photo- and Vapo-chromic Behavior of Luminescent Platinum Complexes Based on the Linkage Isomerization  [Invited]
    KATO Masako
    the 14th Asian Chemical Congress (14ACC)  2011/09
  • Vapor-induced Multichromic Luminescence of Platinum(II) Complexes with Dicarboxybipyridine  [Invited]
    KATO Masako
    The 3rd International Conference of the OCU Advanced Research Institute for Natural Science and Technology (OCARINA)  2011/03  Osaka
  • 発光性金属錯体が発現する特異なクロミック現象  [Invited]
    筑波大学大学院錯体分子化学セミナー  2011/01  筑波
  • 発光性金属錯体の化学  [Invited]
    筑波大学化学セミナー  2011/01  筑波
  • 2010 International Chemical Congress of Pacific Basin Societies  2010/12  Hawaii,USA  カナダ化学会、アメリカ化学会、日本化学会、オーストラリア化学会、ニュージーランド化学会、韓国化学会、中国化学会
  • “Vapor-induced Multichromic Luminescence of Platinum(II) Complexes with Dicarboxybipyridine”  [Invited]
    KATO Masako
    The 4th GCOE International Symposium "Towards a Sustainable Future"  2010/11  Sapporo
  • 発光性クロミック金属錯体  [Invited]
    加藤 昌子
    第6回学際領域における分子イメージングフォーラム  2010/11  調布
  • Luminescent Platinum Complexes Having Sensing Functionalities  [Invited]
    KATO Masako
    16th Malaysian Chemical Congress (16MCC)  2010/10  Kuala Lumpur
  • 発光性金属錯体が発現する特異なクロミック現象  [Invited]
    第60回錯体化学討論会シンポジウム、クロモトロピック姻族錯体の最前線、2  2010/09  大阪
  • Luminescent photochromic behavior of a dinuclear copper(I) complex containing dimethyl sufoxide  [Invited]
    KATO Masako, W.Kamada, Atsushi Kobayashi, Yuko Chishina, Kiyoshi Tsuge
    The 5th Nanjing University - Hokkaido University Joint Symposium and 2009 Nanjing - AHNU - Hokkaido GCOE - NIMS-MANA Joint Symposium –Progress in Advanced Chemistry  2009/11  Nanjing&Wuhu,China
  • “Luminescent photochromic behavior of a dinuclear copper(I) complex containing dimethyl sulfoxide”  [Invited]
    Masako Kato, W, Kamada, Atsushi Kobayashi, Yuko Chishina, Kiyoshi Tsuge
    18th International Symposium on the Photochemistry and Photophysics of Coordination Compounds  2009/07  Sapporo,Japan
  • KATO Masako
    7th Japan-China Joint Symposium on Metal Cluster Compounds (JCSMCC2008)  2008/10  Sapporo,Japan
  • 化学的刺激に応答する発光性白金錯体  [Invited]
    加藤 昌子
    第30回光化学若手の会  2008/06  福岡  光化学協会
  • 環境感応型発光性白金錯体  [Invited]
    加藤 昌子
    大阪市立大学化学談話会  2007/12  大阪
  • Emissive Properties of Silver(Ⅰ)Halide Complexes Containing {Ag2(μ-X)2}Diamond Cores(X=Cl,Br,I)  [Invited]
    K.Tsuge, S.Shibata, M.Kato, S.ishizaka, N.Kitamura, Y.Sasaki
    The 3rd Nanjing-Hokkaido University Joint Symposium  2007/11  Nanjing&Yangzhou,China
  • Solvatochromic Luminescence Based on the Excimer Formation of Bipyridine Platinum(II) Complexes with Linear Alkyl Chain  [Invited]
    M.Kato, Y.Shishido, Y.Ishida, S.Kishi
    The 3rd Nanjing-Hokkaido University Joint Symposium  2007/11  Nanjing&Yangzhou
  • Three-dimensional Network Structures and Vapochromic Behavior of Dicyano(4,4'-dicarboxy-2,2'-bipyridine)platinum(II)  [Invited]
    M.Kato,S.kishi, Y.Wakamatsu, R.Joraku, K.Tsuge
    1st Asian Conference on Coordination Chemistry (ACCC)  2007/07  Okazaki,Japan
  • 環境感応型発光性白金錯体の開発と機能  [Invited]
    加藤 昌子
    近畿大学化学コース講演会  2007/07  東大阪
  • 環境感応型発光性白金錯体の開発と機能  [Invited]
    加藤 昌子
    第24回ライラックセミナー  2007/06  小樽市
  • Luminescent Platinum Complexes Having Sensing Functionalities  [Invited]
    KATO Masako
    Second International Minisymposium on Coordination Chemistry for Advanced Materials  2007/04  Sagamihara,Japan
  • 環境感応型発光性白金錯体の開発と機能  [Invited]
    加藤 昌子
    吉川先生退職記念シンポジウム  2007/04  岡山
  • 環境感応型発光性白金錯体の構築と機能  [Invited]
    加藤 昌子
    第42回氷雪セミナー  2007/01  札幌
  • Vapor-induced Luminescence Switching and Its Unique Mechanism for a Dinuclear (Bipyridine)platinum(II) Complex  [Invited]
    KATO Masako
    3rd International Forum, New Waves in Supramolecular Chemistry and Superstructured Materials  2006/12  Kumamoto,Japan
  • Outstanding Vapochromism of Dicyano(4,4'-dicarboxy-2,2'-bipyridine)platinum(II) with a Three-dimensional Network Structure  [Invited]
    KATO Masako
    Japan-China Joint Symposium on Modern Chemistry (2nd Hokkaido University Nanjing University Joint Symposium)  2006/11  Sapporo,Japan
  • “Vapor-induced Luminescence Switching and Its Unique Mechanism for a Dinuclear (Bipyridine)platinum(II) Complex”  [Invited]
    KATO Masako
    The Sixth China-Japan Joint Symposium on Metal Cluster Compounds  2006/10  Huangshan,China
  • “Vapor-induced Luminescence Switching and Its Unique Mechanism for a Dinuclear (Bipyridine)platinum(II) Complex”,  [Invited]
    KATO Masako
    13th International SPACC-CSJ Symposium  2006/08  Sapporo,Japan
  • Structures and Luminescence Properties of Bipyridine Platinum(II) Complexes with Long Alkyl Chains  [Invited]
    KATO Masako
    The 2005 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2005)  2005/12  Honolulu,USA
  • Structural Approach to the Vapochromism in Luminescent Dinuclear (Diimine)platinum(II) Complexes Bridged with Pyridinethiolate Ions  [Invited]
    KATO Masako
    The 2005 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2005)  2005/12  Honolulu,USA
  • Vapor-induced Luminescence Switching of the Crystalline Syn Isomer of a Dinuclear (Bipyridine)platinum(II) Complex Bridged with Pyridine-2-thiolate Ions  [Invited]
    KATO Masako
    21 COE International Symposium  2004/06  Sendai,Japan

MISC

  • Kato M  Kobunshi  64-  (2)  2015  [Refereed][Not invited]
  • ルテニウム錯体触媒上で水から酸素をどうつくる?
    化学  Vol. 65-  (No. 1)  72  -73  2010  [Not refereed][Not invited]
  • 発光をスイッチする白金(II)複核錯体のベイパー誘起構造変換
    日本結晶学会誌  Vol. 51-  (No. 1)  48  -49  2009  [Not refereed][Not invited]
  • 教育と化学  Vol. 57-  (No. 10)  464  -465  2009  [Not refereed][Not invited]
  • 化学的刺激に応答する発光性白金錯体
    光化学  Vol.38-  (No.2)  97  -102  2007  [Not refereed][Not invited]
  • Masako Kato  Topics in Stereochemistry  25-  351  -373  2006  [Not refereed][Not invited]
  • 環境感応型発光性白金錯体の開発
    化学工業  56-  260  -264  2005  [Not refereed][Not invited]
  • ベイポクロミズム―気体分子により誘起される発色・発光変化
    現代化学  6-  25  -30  2005  [Not refereed][Not invited]
  • 『新規クロミック材料の設計・機能・応用』<監修 関 隆広>
    シーエムシー出版  2005  [Not refereed][Not invited]
  • トリス(ジイミン)ルテニウム(II)錯体を鋳型としたユニークな[2]カテナン
    化学と工業  56-  1000  2003  [Not refereed][Not invited]
  • 光る白金錯体の魅力
    学術月報  54-  911  -912  2001  [Not refereed][Not invited]
  • 気体分子や溶媒に感応して固体状態で発光変化を示す金属錯体
    光化学  32-  147  -149  2001  [Not refereed][Not invited]
  • 有機EL素子はどのようにして光るのか?−電気化学発光の検討
    化学  54-  65  -66  1999  [Not refereed][Not invited]
  • DNAにインターカレートして“光スイッチ”挙動を示すルテニウム(II)錯体
    化学  50-  314  1995  [Not refereed][Not invited]
  • UNICS IIIシステムによる単結晶X線構造解析
    奈良女子大学情報処理センター広報  4-  60  -69  1992  [Not refereed][Not invited]
  • 有機化合物および配位化合物の立体構造と機能
    現代化学  12-  14  -19  1990  [Not refereed][Not invited]
  • かご型構造によるルテニウム(II)-ポリピリジン錯体の光化学的な安定化
    化学と工業  43-  1905  -1906  1990  [Not refereed][Not invited]

Industrial Property Rights

  • 特願2011-103136:希土類錯体ポリマー及びプラスチック成形体  2011年/05/02
  • 特開2005-259377:有機エレクトロルミネッセンス素子  2005/09/22
  • 特許第5009465号:環境感応型発光性ジイミン白金複核錯体  
    加藤 昌子

Research Grants & Projects

  • Control of Stimulus-response and Functionalization of Luminescent Smart Soft Crystals
    Japan Society for the Promotion of Science:Grant in Aid for Scientific Research
    Date (from‐to) : 2017/07 -2022/03 
    Author : KATO Masako
  • Soft Crystals: Science and Photofunctions of Flexible Response Systems with High Order
    Japan Society for the Promotion of Sicence:Grant in Aid for Scientific Research
    Date (from‐to) : 2017/07 -2022/03 
    Author : KATO Masako
  • 動的秩序を基盤をする発光性クロミック金属錯体の創製
    Date (from‐to) : 2013 
    Author : 加藤 昌子
  • 元素活用型3d金属錯体水素発生光触媒の構築
    科学研究費補助金
    Date (from‐to) : 2013 
    Author : 加藤 昌子
  • 動的秩序を基盤とする発光性クロミック金属錯体の創製
    科学研究費補助金
    Date (from‐to) : 2011
  • 1
    Grant-in-Aid for Scientific Research
    Date (from‐to) : 2011
  • 貴金属フリー・ナノハイブリッド触媒の創製
    研究開発事業委託費
    Date (from‐to) : 2008

Educational Activities

Teaching Experience

  • Advanced Inorganic Chemistry
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 総合化学院
    キーワード : 金属錯体,発光,光機能,構造,配位化合物
  • Advanced Chemistry
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 総合化学院
    キーワード : Electrochemistry, Elecrtocatalisis, In situ surface probe, microbial extracellular electron transport (EET)
  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : Electrochemistry, Elecrtocatalisis, In situ surface probe, microbial extracellular electron transport (EET)
  • Modern Trends in Chemical Sciences and Engineering II
    開講年度 : 2018
    課程区分 : 博士後期課程
    開講学部 : 総合化学院
    キーワード : Electrochemistry, Elecrtocatalisis, In situ surface probe, microbial extracellular electron transport (EET)
  • Chemistry I
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 原子の構造、原子軌道、化学結合、混成軌道、物質の三態、電解質溶液
  • Inorganic Chemistry Ⅱ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 無機化学、酸塩基、酸化還元、配位化合物、金属錯体
  • Inorganic Chemistry III
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 無機化学、周期表、典型元素、遷移元素

Campus Position History

  • 2015年4月1日 
    2017年3月31日 
    研究戦略室室員

Position History

  • 2015年4月1日 
    2017年3月31日 
    研究戦略室室員


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