Shigeru Nagase

Fukui Institute for Fundamental Chemistry, Kioto, Kyōto, Japan

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Publications (583)2380.53 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: [11]Cycloparaphenylene ([11]CPP) selectively encapsulates La@C82 to form the shortest possible metallofullerene–carbon nanotube (CNT) peapod, La@C82⊂[11]CPP, in solution and in the solid state. Complexation in solution was affected by the polarity of the solvent and was 16 times stronger in the polar solvent nitrobenzene than in the nonpolar solvent 1,2-dichlorobenzene. Electrochemical analysis revealed that the redox potentials of La@C82 were negatively shifted upon complexation from free La@C82. Furthermore, the shifts in the redox potentials increased with polarity of the solvent. These results are consistent with formation of a polar complex, (La@C82)δ−⊂[11]CPPδ+, by partial electron transfer from [11]CPP to La@C82. This is the first observation of such an electronic interaction between a fullerene pea and CPP pod. Theoretical calculations also supported partial charge transfer (0.07) from [11]CPP to La@C82. The structure of the complex was unambiguously determined by X-ray crystallographic analysis, which showed the La atom inside the C82 near the periphery of the [11]CPP. The dipole moment of La@C82 was projected toward the CPP pea, nearly perpendicular to the CPP axis. The position of the La atom and the direction of the dipole moment in La@C82⊂[11]CPP were significantly different from those observed in La@C82⊂CNT, thus indicating a difference in orientation of the fullerene peas between fullerene–CPP and fullerene–CNT peapods. These results highlight the importance of pea–pea interactions in determining the orientation of the metallofullerene in metallofullerene–CNT peapods.
    Chemistry 09/2014; · 5.93 Impact Factor
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    ABSTRACT: The neutral triple-decker ruthenocenes and anionic ruthenocene bearing a stannole dianion were successfully synthesized by the reactions of dilithiostannoles with [Cp*RuCl]4. This is the first example of a transition-metal complex bearing a group 14 metallole dianion with μ-ŋ(5):ŋ(5) coordination mode, which cannot be achieved using the original Cp ligand. These complexes were fully characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. In the complexes, each of the ruthenium atoms is co-ordinated by the stannole ring in an ŋ(5)-fashion. The aromaticity of the stannole dianion moieties is retained judging from no C-C bond alternation in the stannole rings. CH/π interaction was found in the packing structure of the SiMe3 derivative, which leads to a well-ordered column-like structure. The oxidation wave of the triple-decker complex was observed at -0.43 V (vs. ferrocene), which reveals that the triple-decker type heavy ruthenocene is oxidized more easily than the ferrocene. Comparison of the oxidation potential between the triple-decker complex and decamethyl-ruthenocene (Cp*2Ru, Cp* = ŋ(5)-C5Me5-) reveals that a stannole ligand functions as an electron-donating ligand much stronger than the conventional electron-rich Cp* ligand.
    Journal of the American Chemical Society 08/2014; · 10.68 Impact Factor
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    ABSTRACT: Reactions of Sc3N@Ih-C80 with aziridine derivatives were conducted to afford the corresponding mono-adducts. A pair of diastereomers of the mono-adduct [5,6]-pyrrolidino-Sc3N@Ih-C80 was isolated and characterized by means of mass spectrometry, Vis-NIR absorption spectroscopy, and electrochemical measurements. Structural analysis of the mono-adducts was conducted by NMR and single-crystal X-ray structure determinations.
    Chemical Communications 08/2014; · 6.38 Impact Factor
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    ABSTRACT: Regioselective cycloaddition of adamantylidene carbene to Pr@C2v(9)-C82 affords the first derivative of praseodymium-containing metallofullerenes. Single-crystal X-ray crystallographic data in combination with theoretical studies demonstrate that the addition is dictated by the single metal ion encapsulated inside the fullerene cage.
    Chemical Communications 07/2014; · 6.38 Impact Factor
  • Tao Yang, Xiang Zhao, Shigeru Nagase, Takeshi Akasaka
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    ABSTRACT: The reaction mechanism and regioselectivity of the Diels–Alder reactions of C68 and Sc3N@C68, which violate the isolated pentagon rule, were studied with density functional theory calculations. For C68, the [5,5] bond is the most favored thermodynamically, whereas the cycloaddition on the [5,6] bond has the lowest activation energy. Upon encapsulation of the metallic cluster, the exohedral reactivity of Sc3N@C68 is reduced remarkably owing to charge transfer from the cluster to the fullerene cage. The [5,5] bond becomes the most reactive site thermodynamically and kinetically. The bonds around the pentagon adjacency show the highest chemical reactivity, which demonstrates the importance of pentagon adjacency. Furthermore, the viability of Diels–Alder cycloadditions of several dienes and Sc3N@C68 was examined theoretically. o-Quinodimethane is predicted to react with Sc3N@C68 easily, which implies the possibility of using Diels–Alder cycloaddition to functionalize Sc3N@C68.
    Chemistry - An Asian Journal 07/2014; · 4.57 Impact Factor
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    ABSTRACT: The endohedral fullerene once erroneously identified as Sc3@C82 was recently shown to be Sc3C2@Ih-C80, the first example of an open-shell cluster metallofullerene. We herein report that benzylbromide (1) reacts with Sc3C2@ Ih-C80 via a regioselective radical addition that affords only one isomer of the adduct Sc3C2@Ih-C80(CH2C6H5) (2) in high yield. An X-ray crystallographic study of 2 demonstrated that the benzyl moiety is singly bonded to the fullerene cage, which eliminates the paramagnetism of the endohedral in agreement with the ESR results. Interestingly, X-ray results further reveal that the three-fold disordered Sc3C2 cluster adopts two different configurations inside the cage. These configurations represent the so-called "planar" form and the computationally predicted, but not crystallographically characterized, "trifoliate" form. It is noteworthy that this is the first crystallographic observation of the "trifoliate" form for the Sc3C2 cluster. In contrast, crystallographic investigation of a Sc3C2@Ih-C80/Ni(OEP) cocrystal, in which the endohedral persists in an open-shell structure with paramagnetism, indicates that only the former form occurs in pristine Sc3C2@ Ih-C80. These results demonstrate that the cluster configuration in EMFs is highly sensitive to the electronic structure, which is tunable by exohedral modification. In addition, the electrochemical behavior of Sc3C2@Ih-C80 has been markedly changed by the radical addition, but the absorption spectra of the pristine and the derivative are both featureless. These results suggest that the unpaired electron of Sc3C2@Ih-C80 is buried in the Sc3C2 cluster and does not affect the electronic configuration of the cage.
    Journal of the American Chemical Society 07/2014; · 10.68 Impact Factor
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    ABSTRACT: The spectrum-detected smallest sulfide clusterfullerene Sc2S@C68 has not been characterized yet. Herein, we explored a series of Sc2S@C68 species to determine which could be the most promising isomer. The results suggest that a sulfide cluster encapsulated in the C2v(6073)-C68 cage which violates the isolated pentagon rule (IPR) with two opposite pentalenes has the lowest energy and an overwhelming thermodynamic stability. Two scandium atoms coordinate with the two opposite pentalenes, leading to an obtuse Sc-S-Sc angle of 151°. The bond lengths of the two Sc-S bonds are equivalent. Frontier molecular orbital distributions exhibit substantial overlaps between metallic orbitals and cage orbitals, indicating that covalent interactions cannot be ignored, which have been unambiguously identified in terms of Mayer bond order and bonding critical point (BCP) indicator methods. Electrochemical properties as well as (13)C NMR, UV-vis-NIR, and IR spectra of Sc2S@C2v(6073)-C68 have been theoretically studied to assist further experimental characterization.
    Physical Chemistry Chemical Physics 06/2014; · 4.20 Impact Factor
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    ABSTRACT: In terms of density functional theory combined with statistic mechanics computations, we investigated a dimetallic sulfide endohedral fullerene Sc2S@C76 which has been synthesized without any characterization in experiments. Our theoretical study reveals that Sc2S@Td(19151)-C76 which satisfies the isolated-pentagon rule (IPR) possesses the lowest energy, followed by three non-IPR structures (Sc2S@C2v(19138)-C76, Sc2S@Cs (17490)-C76, and Sc2S@C1(17459)-C76). To clarify the relative stabilities of those isomers at high temperatures, enthalpy–entropy interplay has been taken into consideration. Calculation results indicate that three species Sc2S@Td(19151)-C76, Sc2S@C2v(19138)-C76, and Sc2S@C1(17459)-C76 have noticeable molar fractions at the fullerene-formation temperature region (500–3000K), and the Sc2S@C1(17459)-C76 with one pentagon pair becomes the most predominant isomer above 1800 K, suggesting that the unexpected non-IPR structure is thermodynamically favorable at elevated temperatures. In addition, the structural characteristics, electron features, UV-vis-NIR adsorptions, and 13C NMR spectra of those three stable structures are introduced to assist experimental identification and characterization in future. © 2014 Wiley Periodicals, Inc.
    Journal of Computational Chemistry 06/2014; · 3.84 Impact Factor
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    ABSTRACT: Dilithiostannoles, which are aromatic tin-containing ring compounds, were proposed to have stannylene character, as judged from their NMR analysis. We herein report on the synthesis of silyl-substituted dilithiostannoles, which were characterized by NMR spectroscopy and X-ray diffraction analysis. The silyl-substituted derivatives also exhibit features characteristic of aromatic dilithiostannoles such as 7Li NMR signals at high-field area and no C–C bond alternation in the stannole rings. Theoretical calculations and the 119Sn NMR chemical shifts revealed that the stannylene character in the silyl-substituted dilithiostannoles is enhanced due to greater interaction between 5p (Sn) and LUMO (butadiene) in comparison to those in alkyl and aryl derivatives. The 119Sn Mössbauer spectra of dilithiostannoles were measured for the first time, indicating that each of the tin atoms in dilithiostannoles can be characterized as having Sn(II) character.
    Organometallics 05/2014; 33(11):2910–2913. · 4.15 Impact Factor
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    ABSTRACT: The geometries of fullerenes are governed by the isolated pentagon rule (IPR), which states that stable fullerenes have each of their 12pentagons surrounded by five hexagons. At the dawn of fullerene science, it was widely believed that the IPR would also be applicable for endohedral fullerenes. In 2000, the idea was altered by the discovery of first non-IPR fullerenes, Sc2@C66 and Sc3N@C68. The structural data for Sc2@C66 were interpreted to indicate the possession of a pair of doubly fused pentagons. However, that structure has persisted as a long-standing mystery, since it is thermodynamically unfavorable. Here, we demonstrate definitively that Sc2@C66 is not a long-believed structure but a brand-new type. 2D-NMR spectroscopic and single-crystal X-ray analyses disclose that Sc2@C66 has a C2v(4059)-C66 cage containing two sets of unsaturated linear triquinanes (ULTs) where three pentagons abut one another and two scandium ions are located within the folds of each of the ULT units.
    Journal of the American Chemical Society 05/2014; · 10.68 Impact Factor
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    ABSTRACT: This report describes the photochemical behavior of single-walled carbon nanotubes (SWNTs) in the presence of propylamine. The SWNTs are characterized by absorption and Raman spectroscopy. The spectral changes due to photoirradiation indicate that reactions occur predominantly with the metallic SWNTs and small-diameter SWNTs. The detection of amine radicalcation species by ESR spectroscopy reveals photoinduced electron transfer from the amine to the excited SWNTs. After exposure of the photoirradiated SWNTs to air, the characteristic spectra were recovered, except for that of the small-diameter SWNTs. The results suggest that, after photoreduction of the SWNTs, subsequent selective sidewall functionalization of the small-diameter SWNTs occurs.
    ChemPhysChem 04/2014; · 3.35 Impact Factor
  • Yi-Jun Guo, Tao Yang, Shigeru Nagase, Xiang Zhao
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    ABSTRACT: The geometric, electronic structure, and thermodynamic stability of Gd2C94 species, including dimetallofullerenes Gd2@C94 and carbide clusterfullerenes Gd2C2@C92, have been systematically investigated by a density functional theory approach combined with statistical mechanics calculations. Although the Gd2@C2(153480)-C94 is determined to possess the lowest energy, its molar fraction at the temperature region of fullerene formation is extremely low if the temperature effect is taken into consideration. Meanwhile, three C92-based carbide clusterfullerene species, Gd2C2@D3(126408)-C92, Gd2C2@C1(126390)-C92, and Gd2C2@C2(126387)-C92, with some higher energy are exposed to possess considerable thermodynamic stabilities within a related temperature interval, suggesting that carbide clusterfullerenes rather than dimetallofullerenes could be isolated experimentally. Although one isomer, Gd2C2@D3(126408)-C92, has been indeed obtained experimentally, a novel structure, Gd2C2@C1(126390)-C92, behaving as the most abundant isomer at more elevated temperatures with the largest SOMO-LUMO gap, is predicted for the first time to be another proper isomer isolated in the experiment. Moreover, in order to further analyze the interaction between gadolinium atoms and carbon atoms in either a carbide cluster or a fullerene cage, frontier molecular orbital, natural bond orbital, and Mayer bond order analyses have been employed, and the results show that the covalent interaction cannot be neglected. The IR spectra of Gd2C2@C92 have been simulated to provide some valuable guidance for future experiments.
    Inorganic Chemistry 02/2014; · 4.59 Impact Factor
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    ABSTRACT: Recently, an extraction of la metallofullerenes from soot using 1,2,4-trichlorobenzene has been reported for La@C80 and La@C82. In both cases, the cages were derivatized by the solvent (forming La@C80-C6H3Cl2 and La@C82-C6H3Cl2) and the following X-ray analysis disclosed rather unexpected cages: C80(C 2v ;3) and C82(C 3v ;7). In order to explain the challenging observations, a two-step computational treatment is presented. The first step deals with the high-temperature gas-phase formation of the underivatized endohedrals while the second step models the reaction with the solvent. The Gibbs free energies were evaluated for representative temperatures and the computational scheme was able to confirm high relative populations for the observed derivatized cages.
    Fullerenes Nanotubes and Carbon Nanostructures 01/2014; 22. · 0.76 Impact Factor
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    ABSTRACT: Endohedral metallofullerenes (EMFs) encapsulating divalent metal ions have rarely been studied because of their low production yields. We report here for the first time the chemical understanding of two typical divalent EMFs, i.e. Yb@D3h-C74 and Yb@C2(13)-C84 with a disilirane reagent (1), which has shown great success in probing the chemical reactivity of EMFs encapsulating a variety of metallic cores. It was surprising to find that Yb@D3h(1)-C74 reacted with 1 neither thermally nor photochemically under normal conditions, showing an unusually low reactivity. However, monoadduct formation was achieved by laser-irradiation of their mixtures during the mass spectroscopic measurement. Accordingly, the thermal and photochemical reactions of Yb@C2(13)-C84 with 1 were conducted under harsher conditions and monoadduct formation was confirmed by both chromatographic and mass spectroscopic studies. The relatively low reactivity of these divalent EMFs compared with that of the corresponding trivalent analogues is attributed to their more negative first reduction potentials, as well as their close-shell electronic configurations, presenting new insights into the templating effect of the internal metal ion on the chemical properties of the cage carbons of EMFs.
    Fullerenes Nanotubes and Carbon Nanostructures 01/2014; 22. · 0.76 Impact Factor
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    ABSTRACT: Recently, a new member of the lanthanum-containing metallofullerene family has been isolated and its structure determined from X-ray crystallographic analysis, namely La@C(,17490), even with two pairs of connected pentagons, hence violating the isolated-pentagon rule (IPR). In order to explain the interesting observation, a computational treatment is suggested for evaluations of the relative populations of nonisomeric metallofullerenes. As a comparative reference structure, the most stable La@C isomer is selected — the IPR-C()-cage based endohedral La@C(). In the relevant temperature region, the La@C(,17490) species should be considerably more populated compared to La@C(). The new computational stability treatment is applicable to a wider spectrum of nonisomeric metallofullerenes.
    Fullerenes Nanotubes and Carbon Nanostructures 01/2014; 22. · 0.76 Impact Factor
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    ABSTRACT: Density-functional theory (DFT) calculations are reported for Sm@C74, namely for Sm encapsulation in the IPR (isolated pentagon rule) C74 cage and in two C74 cages with a pentagon-pentagon junction. Their relative thermodynamic production yields are evaluated using the DFT calculated terms and it is shown that the IPR-based Sm@C74 endohedral prevails at relevant temperatures in agreement with observation, however, isolation of a minor isomer could be possible.
    Fullerenes Nanotubes and Carbon Nanostructures 01/2014; 22. · 0.76 Impact Factor
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    ABSTRACT: Relative concentrations of the nine IPR-based (isolated-pentagon-rule) isomers of Yb@C82 are computed from the Gibbs energy derived from partition functions supplied with parameters from density functional theory calculations. A good agreement with experiment is found at elevated temperatures where the Yb-endohedrals based on the C 2v ;9 and Cs(C);6 C82 cages exhibit comparable concentrations while the third observed species based on the C 2(C);5 cage has about one half of their populations though still a significant presence. The result is somewhat sensitive to the partition-function description.
    Fullerenes Nanotubes and Carbon Nanostructures 01/2014; 22. · 0.76 Impact Factor
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    ABSTRACT: Although all the pure-carbon fullerene isomers above C60 reported to date comply with the isolated pentagon rule (IPR), non-IPR structures, which are expected to have different properties from those of IPR species, are obtainable either by exohedral modification or by endohedral atom doping. This report describes the isolation and characterization of a new endohedral metallofullerene (EMF), La2 @C76 , which has a non-IPR fullerene cage. The X-ray crystallographic result for the La2 @C76 /[Ni(II) (OEP)] (OEP=octaethylporphyrin) cocrystal unambiguously elucidated the Cs (17 490)-C76 cage structure, which contains two adjacent pentagon pairs. Surprisingly, multiple metal sites were distinguished from the X-ray data, which implies dynamic behavior for the two La(3+) cations inside the cage. This dynamic behavior was also corroborated by variable-temperature (139) La NMR spectroscopy. This phenomenon conflicts with the widely accepted idea that the metal cations in non-IPR EMFs invariably coordinate strongly with the negatively charged fused-pentagon carbons, thereby providing new insights into modern coordination chemistry. Furthermore, our electrochemical and computational studies reveal that La2 @Cs (17 490)-C76 has a larger HOMO-LUMO gap than other dilanthanum-EMFs with IPR cage structures, such as La2 @D3h (5)-C78 and La2 @Ih (7)-C80 , which implies that IPR is no longer a strict rule for EMFs.
    Chemistry 12/2013; 19(50):17125-30. · 5.93 Impact Factor
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    ABSTRACT: Regioselective properties of a D2d-C84 in multistep [4 + 2] cycloadditions and the applications of bis-functional C84 derivatives were investigated. Density functional calculations demonstrate that an indene-C84 bisadduct is a promising electron acceptor in organic solar cells and a C84-bis-anthracene copolymer can be utilized as a charge-transfer material.
    Organic Letters 12/2013; · 6.14 Impact Factor
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    ABSTRACT: Electronic and molecular structure calculations of 51 selected Yb@C84 isomers are presented. The obtained energies and structural parameters are used for calculation of the temperature dependence of Gibbs energies and the equilibrium composition of the isomeric mixture. Applied to the temperaturerange 1500–2000 K relevant for the conventional electric-arc preparation technique, the prevailing isomers are identified and compared with the available experimental observations. An assignment of the experimentally unidentified one is also suggested.
    physica status solidi (b) 12/2013; 250(12). · 1.49 Impact Factor

Publication Stats

4k Citations
2,380.53 Total Impact Points

Institutions

  • 2012–2014
    • Fukui Institute for Fundamental Chemistry
      Kioto, Kyōto, Japan
    • Soochow University (PRC)
      Wu-hsien, Jiangsu Sheng, China
    • The University of Electro-Communications
      • Department of Applied Physics and Chemistry
      Tokyo, Tokyo-to, Japan
  • 2006–2014
    • Kyoto University
      • • Fukui Institute for Fundamental Chemistry
      • • Institute for Chemical Research
      Kioto, Kyōto, Japan
    • The Graduate University for Advanced Studies
      • Department of Structural Molecular Science
      Миура, Kanagawa, Japan
  • 2012–2013
    • Huazhong University of Science and Technology
      • State Key Laboratory of Material Processing and Die & Mould Technology
      Wuhan, Hubei, China
  • 2011–2013
    • Xi'an Jiaotong University
      • Department of Chemistry
      Xi’an, Shaanxi Sheng, China
    • Northeast Institute of Geography and Agroecology
      • Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety
      Beijing, Beijing Shi, China
    • National Institutes Of Natural Sciences
      Edo, Tōkyō, Japan
  • 2008–2013
    • University of California, Davis
      • Department of Chemistry
      Davis, California, United States
    • Kinki University
      Ōsaka, Ōsaka, Japan
  • 2005–2013
    • Saitama University
      • Department of Chemistry
      Saitama, Saitama, Japan
  • 2004–2013
    • Friedrich-Alexander Universität Erlangen-Nürnberg
      • Computer-Chemistry-Center
      Erlangen, Bavaria, Germany
    • Athens State University
      Athens, Alabama, United States
    • University of Georgia
      • Center for Computational Chemistry
      Athens, GA, United States
  • 2001–2013
    • Hiroshima University
      • Division of Chemistry
      Hirosima, Hiroshima, Japan
    • Toyohashi University of Technology
      • Department of Knowledge-based Information Engineering
      Toyohasi, Aichi, Japan
  • 1989–2013
    • University of Tsukuba
      • Graduate School of Pure and Applied Sciences
      Tsukuba, Ibaraki, Japan
  • 2004–2012
    • Peking University
      • • School of Physics
      • • College of Chemistry and Molecular Engineering
      Beijing, Beijing Shi, China
  • 2003–2012
    • Tokyo Gakugei University
      Koganei, Tōkyō, Japan
    • University of Prince Edward Island
      Charlottetown, Prince Edward Island, Canada
  • 2010
    • University of California, Santa Barbara
      • Department of Chemistry and Biochemistry
      Santa Barbara, CA, United States
    • Rensselaer Polytechnic Institute
      • Department of Physics, Applied Physics, and Astronomy
      New York City, NY, United States
    • Complutense University of Madrid
      • Departamento de Química Orgánica I
      Madrid, Madrid, Spain
  • 2008–2010
    • University of Pune
      • Department of Chemistry
      Pune, State of Maharashtra, India
  • 2006–2010
    • National Chung Cheng University
      Chia-i-hsien, Taiwan, Taiwan
  • 2001–2010
    • The University of Tokyo
      • • Faculty of Science and Graduate School of Science
      • • Department of Chemistry
      Tokyo, Tokyo-to, Japan
  • 2009
    • Yale University
      • Department of Chemistry
      New Haven, CT, United States
  • 1993–2009
    • Tokyo Metropolitan University
      • Department of Chemistry
      Edo, Tōkyō, Japan
  • 2002–2008
    • Institute for Molecular Science
      Okazaki, Aichi, Japan
    • Kyushu University
      • Graduate School of Sciences
      Fukuoka-shi, Fukuoka-ken, Japan
  • 2005–2007
    • National Institute of Advanced Industrial Science and Technology
      • Computational Biology Research Center
      Tsukuba, Ibaraki, Japan
  • 2001–2007
    • Academia Sinica
      • Institute of Chemistry
      Taipei, Taipei, Taiwan
  • 2004–2006
    • Nagoya University
      • Graduate School of Environmental Studies
      Nagoya-shi, Aichi-ken, Japan
  • 1997–2004
    • Niigata University
      • Graduate School of Science and Technology
      Niahi-niigata, Niigata, Japan
  • 2000
    • Kitasato University
      • Department of Chemistry
      Edo, Tōkyō, Japan
  • 1981–1995
    • Yokohama National University
      Yokohama, Kanagawa, Japan
  • 1990–1994
    • Japan Automobile Research institute
      Ibaragi, Ōsaka, Japan
  • 1987–1988
    • Tokyo Metropolitan Institute of Gerontology
      Edo, Tōkyō, Japan