Shigeru Nagase

Huazhong University of Science and Technology, Wu-han-shih, Hubei, China

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Publications (640)3226.89 Total impact

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    ABSTRACT: The X-ray structure analysis of arenecarbochalcogenoic acids (ArCOEH and ArCEOH, E = S, Se, Te) is successful for 4-MeC6H4COSH for the first time, which reveals that the syn-conformer forms a planar cyclic dimer with two S–H⋯O=C hydrogen bonds in the solid state. Density functional theory calculations are performed for benzenecarbochalcogenoic acids (C6H5COEH and C6H5CEOH), the tetrahydrofuran (THF)-solvated acids, and the cyclic dimers of the acids. It is suggested that arenechalcogenol acids (ArCOEH) form cyclic dimers in the solid state, although Della Védova and coworkers reported that catemeric hydrogen-bonding chains are observed for the crystal structures of selenoacetic acid (MeCOSeH). Calculations demonstrate that arenecarbochalcogenoic acids exist predominantly as chalcogenoxo tautomers (ArCEOH) in polar solvents such as THF especially at low temperatures, unlike the solid state cases, which are consistent with several experimental results.
    No preview · Article · Jan 2016 · Bulletin of the Chemical Society of Japan

  • No preview · Article · Dec 2015 · The Journal of Physical Chemistry C
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    ABSTRACT: Stable selenenyl-chlorophosphines, bearing a silylalkyl group, were synthesized. Subsequent treatment with Lewis acids such as AlCl3 afforded the corresponding phosphaalkenes. A reaction mechanism that proceeds through an intramolecular 1,2-elimination of chlorosilane was proposed. Stable selenenyl-chlorophosphines, bearing a trisilylalkyl group, were synthesized, and their treatment with Lewis acids such as AlCl3 afforded the corresponding phosphaalkenes. The experimental results and theoretical calculations suggested that the reaction proceeds through the intramolecular 1,2-elimination of chlorosilanes
    No preview · Article · Dec 2015
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    ABSTRACT: Exohedral derivatization of Lu3N@Ih-C80 was successfully conducted by the photoreactions with disilirane and digermirane. The single-crystal X-ray structural analyses firmly established the 1,4-bis-silylated and bis-germylated structures, which represent rare examples of the crystallographic studies of functionalized Lu3N@Ih-C80. The electrochemical and theoretical studies revealed that the redox properties of the bis-silylated and bis-germylated derivatives were remarkably altered compared to those of the parent Lu3N@Ih-C80. For more details see the Full Paper on page 16411 ff. by M. Kako, M. M. Olmstead, A. L. Balch, S. Nagase, T. Akasaka et al.
    Preview · Article · Nov 2015 · Chemistry - A European Journal
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    ABSTRACT: Extraction of insoluble metallofullerenes, La@C-2n (n = 36-38), was conducted with dichlorobenzene, chlorobenzene, and iodobenzene as a solvent under reflux condition. When iodobenzene was used, La@C-2n (n = 36-38) was successfully extracted as the corresponding phenyl adducts, such as La@C-72(C6H5), La@C-74(C6H5), and La@C-76(C6H5). The number of isomers of corresponding adducts, La@C-72(C6H5) and La@C-74(C6H5), were reduced to one-third of that in 1,2,4-trichlorobenzene extracts, which was reported previously. Based on the spectroscopic analysis, the carbon cages of La@C-72(C6H5) and La@C-74(C6H5) were deduced to be La@C-2(10612)-C-72(C6H5) and La@D-3h-C-74(C6H5), respectively. The addition site carbon possessing very high radical character suggests that the corresponding adducts were produced by the addition of phenyl radical generated from iodobenzene on metallofullerenes.
    No preview · Article · Nov 2015 · Carbon
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    ABSTRACT: Invited for the cover of this issue are the groups of M. Kako (The University of Electro-Communications, Japan), M. M. Olmstead (University of California, USA), A. L. Balch (University of California, USA), S. Nagase (Kyoto University, Japan), T. Akasaka (University of Tsukuba, Japan). The image depicts the 1,4-bis-silylated and 1,4-bis-germylated structures of Lu3 N@Ih -C80 , which represent rare examples of the crystallographic studies of functionalized Lu3 N@Ih -C80 . Read the full text of the article at 10.1002/chem.201502511.
    No preview · Article · Sep 2015 · Chemistry - A European Journal
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    ABSTRACT: The bis(μ-oxo) dimeric complexes {Ar(iPr8)OM(μ-O)}2 (Ar(iPr8) = C6H-2,6-(C6H2-2,4,6-(i)Pr3)2-3,5-(i)Pr2; M = Fe (1), Co (2)) were prepared by oxidation of the M(I) half-sandwich complexes {Ar(iPr8)M(η(6)-arene)} (arene = benzene or toluene). Iron species 1 was prepared by reacting {Ar(iPr8)Fe(η(6)-benzene)} with N2O or O2, and cobalt species 2 was prepared by reacting {Ar(iPr8)Co(η(6)-toluene)} with O2. Both 1 and 2 were characterized by X-ray crystallography, UV-vis spectroscopy, magnetic measurements, and, in the case of 1, Mössbauer spectroscopy. The solid-state structures of both compounds reveal unique M2(μ-O)2 (M = Fe (1), Co(2)) cores with formally three-coordinate metal ions. The Fe···Fe separation in 1 bears a resemblance to that in the Fe2(μ-O)2 diamond core proposed for the methane monooxygenase intermediate Q. The structural differences between 1 and 2 are reflected in rather differing magnetic behavior. Compound 2 is thermally unstable, and its decomposition at room temperature resulted in the oxidation of the Ar(iPr8) ligand via oxygen insertion and addition to the central aryl ring of the terphenyl ligand to produce the 5,5'-peroxy-bis[4,6-(i)Pr2-3,7-bis(2,4,6-(i)Pr3-phenyl)oxepin-2(5H)-one] (3). The structure of the oxidized terphenyl species is closely related to that of a key intermediate proposed for the oxidation of benzene.
    No preview · Article · Sep 2015 · Inorganic Chemistry
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    ABSTRACT: The structures and bonding in the heavier group 14 element olefin analogues [E{CH(SiMe3)2}2]2 and [E{N(SiMe3)2}2]2 (E = Ge, Sn, or Pb) and their dissociation into :E{CH(SiMe3)2}2 and :E{N(SiMe3)2}2 monomers were studied computationally using hybrid density functional theory (DFT) at the B3PW91 with basis set superposition error and zero point energy corrections. The structures were reoptimized with the dispersion-corrected B3PW91-D3 method to yield dispersion force effects. The calculations generally reproduced the experimental structural data for the tetraalkyls with a few angular exceptions. For the alkyls, without the dispersion corrections, dissociation energies of −2.3 (Ge), +2.1 (Sn), and −0.6 (Pb) kcal mol−1 were calculated, indicating that the dimeric E–E bonded structure is favored only for tin. However, when dispersion force effects are included, much higher dissociation energies of 28.7 (Ge), 26.3 (Sn), and 15.2 (Pb) kcal mol−1 were calculated, indicating that all three E–E bonded dimers are favored. Calculated thermodynamic data at 25 °C and 1 atm for the dissociation of the alkyls yield ΔG values of 9.4 (Ge), 7.1 (Sn), and −1.7 (Pb) kcal mol−1, indicating that the dimers of Ge and Sn, but not Pb, are favored. These results are in harmony with experimental data. The dissociation energies for the putative isoelectronic tetraamido-substituted dimers [E{N(SiMe3)2}2]2 without dispersion correction are −7.0 (Ge), −7.4 (Sn), and −4.8 (Pb) kcal mol−1, showing that the monomers are favored in all cases. Inclusion of the dispersion correction yields the values 3.6 (Ge), 11.7 (Sn), and 11.8 (Pb) kcal mol−1, showing that dimerization is favored but less strongly so than in the alkyls. The calculated thermodynamic data for the amido germanium, tin, and lead dissociation yield ΔG values of −12.2, −3.7, and −3.6 kcal mol−1 at 25 °C and 1 atm, consistent with the observation of monomeric structures. Overall, these data indicate that, in these sterically-encumbered molecules, dispersion force attraction between the ligands is of greater importance than group 14 element–element bonding, and is mainly responsible for the dimerization of the metallanediyls species to give the dimetallenes. In addition, calculations on the non-dissociating distannene [Sn{SiMetBu2}2]2 show that the attractive dispersion forces are key to its stability.
    No preview · Article · Aug 2015 · Chemical Science
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    ABSTRACT: The water-dimer formation and its encapsulation into D2(22)-C84 and D2d(23)-C84 fullerenes is evaluated. The water-dimer populations are computed using the potential-energy change from the G3 theory and anharmonic partition functions from the MP2/AUG-cc-pVQZ approach. The encapsulation energetics is treated at the M06-2X/6-31++G** level and it is found that the water-dimer storage in C84 is attractive, yielding an energy gain of more than 10kcal/mol. This substantial encapsulation energy together with the computed temperature increase of the water-dimer population in the saturated steam suggest that the (H2O)2@C84 endohedrals could be produced in a high-temperature/high-pressure approach similarly to encapsulation of rare gases in fullerenes.
    No preview · Article · Aug 2015 · Fullerenes Nanotubes and Carbon Nanostructures
  • Yi-Jun Guo · Hong Zheng · Tao Yang · Shigeru Nagase · Xiang Zhao
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    ABSTRACT: All of C74-based endohedral metallofullerenes (EMFs) are found to be monometallofullerenes with the same D3h(14246)-C74 cage so far. An opening question is whether other C74 cages could survive during the production of some novel C74-EMFs. Theoretically, we studied the trimetallic endohedral fullerene Er3C74, the existence of which had been proven without any further characterizations. Two thermodynamically stable Er3C74 isomers were obtained, both of which could be expressed as Er3@C74, meaning that previously synthesized Er3C74 is indeed an endohedral trierbium fullerene. Besides the isomer with well-known D3h(14246)-C74 cage which obeys isolated pentagon rule (IPR), another one possesses the C1(13771)-C74 cage with two adjacent pentagons. Notably, it is the first time an endohedral metallofullerene containing the C1(13771)-C74 cage has been reported. Frontier orbitals analysis, bonding analysis in terms of quantum theory of atoms-in-molecule (QTAIM) and Mayer bond order, together with two-dimensional maps of electron localization function (ELF) and Laplacian of electron density of Er3@D3h(14246)-C74 and Er3@C1(13771)-C74 show obvious covalent interactions not only between metallic atoms and carbon cage but also among three erbium atoms. Finally, simulated IR spectra of Er3@D3h(14246)-C74 and Er3@C1(13771)-C74 were simulated, which should be useful to distinguish those two isomers.
    No preview · Article · Jul 2015 · Inorganic Chemistry
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    ABSTRACT: The reactions of an anionic heavy ruthenocene with CCl4, MeI, EtBr and Me3SiCl afforded the first stannole monoanion complexes. Surprisingly, coordination modes of the stannole rings are highly dependent on the substituents on the tin atom. The chloro derivative exhibits an η4-fashion-like coordination mode with a bent stannole ring, whereas the trimethylsilyl derivative adopts the conventional η5-coordination mode. Coordination modes of the alkyl derivatives are in between the two types. Cyclic voltamograms for these complexes reveal that an electron donating character of the stannole ligand becomes stronger as the stannole ring becomes planar. Theoretical calculations elucidate that the different coordination modes originate from both electronegativity of an adjacent atom to the tin atom and bulkiness of a substituent on the tin atom.
    No preview · Article · Jul 2015 · Dalton Transactions
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    ABSTRACT: Treatment of 1-bromo-2,3,4,5-tetraethylalumole (1) with 3-hexyne afforded the corresponding product 1-bromo-1-alumacyclonona-2,4,6,8-tetraene (2), accompanied by the formation of hexaethylbenzene. In the crystalline state, 2 forms a Br-bridged dimer with a pseudo C2 -symmetric and twisted AlC8 nine-membered ring. Deuterium-labeling experiments and DFT calculations on the reaction of 1 with 3-hexyne suggested that 1-bromo-1-alumacyclohepta-2,4,6-triene, which is formed by the insertion of one molecule of 1-hexyne into the AlC bond of alumole 1, is the key intermediate for the generation of 2 as well as hexaethylbenzene. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    No preview · Article · Jun 2015 · Angewandte Chemie International Edition
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    ABSTRACT: Treatment of 1-bromo-2,3,4,5-tetraethylalumole (1) with 3-hexyne afforded the corresponding product 1-bromo-1-alumacyclonona-2,4,6,8-tetraene (2), accompanied by the formation of hexaethylbenzene. In the crystalline state, 2 forms a Br-bridged dimer with a pseudo C2-symmetric and twisted AlC8 nine-membered ring. Deuterium-labeling experiments and DFT calculations on the reaction of 1 with 3-hexyne suggested that 1-bromo-1-alumacyclohepta-2,4,6-triene, which is formed by the insertion of one molecule of 1-hexyne into the AlC bond of alumole 1, is the key intermediate for the generation of 2 as well as hexaethylbenzene.
    No preview · Article · Jun 2015 · Angewandte Chemie
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    ABSTRACT: Reaction of the stable digermyne BbtGeGeBbt (Bbt = 2,6-[CH(SiMe3)2]2-4-[C(SiMe3)3]-C6H2) with ethylene initially afforded the corresponding 1,2-digermacyclobutene. Depending on the reaction conditions applied, further reaction of this 1,2-digermacyclobutene with ethylene furnished two different reaction products: a 1,4-digerma-bicyclo[2.2.0]hexane or a bis(germiranyl)ethane. Combined experimental and theoretical results suggested that the 1,4-digerma-bicyclo[2.2.0]hexane and the bis(germiranyl)ethane are the thermodynamic and kinetic reaction products, respectively. A reaction mechanism in agreement with these results is proposed.
    No preview · Article · Jun 2015 · Chemical Science
  • Jing-Dong Guo · Shigeru Nagase · Philip P. Power
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    ABSTRACT: The dissociation of the sterically encumbered diphosphanes and diarsanes [:E{CH(SiMe3)2}2]2 (E = P or As) and [:E{N(SiMe3)2}2]2 (E = P or As) into :Ė{CH(SiMe3)2}2 or :Ė{N(SiMe3)2}2 radical monomers was studied computationally using hybrid density functional theory (DFT) at the B3PW91 with the 6-311+G(d) basis set for P and As, and the 6-31G(d,p) basis set for other atoms. The structures were reoptimized with the dispersion corrected B3PW91-D3 method to estimate dispersion force effects. The calculations reproduced the experimental structural data for the tetraalkyls with good accuracy. Without the dispersion correction, negative dissociation energies of −10.3 and −6.5 kcal mol-1 were calculated for the phosphorus and arsenic tetraalkyls, indicating that the radical monomers are more stable. In contrast, the incorporation of dispersion force effects afforded high, positive dissociation energies of +37.6 and +37.1 kcal mol-1 that favored dimeric structures. The dissociation energies (without dispersion) calculated for the tetraamido-substituted dimer are also negative, but changed to positive values of +29.3 and +32.5 kcal mol-1 upon optimization with the D3 dispersion term. In contrast to earlier calculations, which indicated that the release of accumulated strain energy within the tetraalkyl dimers was the driving force for dissociation to monomers (i.e., the “Jack-in-the-Box” molecular model), the current calculations show that dispersion force attractive interactions exceed those of ligand relaxation and stabilize the dimeric structures. Single-point MP2 (second-order Møller-Plesset perturbation theory) calculations including dispersion effects afforded dissociation energies of 30.4 and 30.8 kcal mol-1 for the tetraalkyl species, suggesting that the addition of the D3 dispersion term to the B3PW91 functional may overestimate such forces by 7-8 kcal mol-1. It is concluded that the balance of dispersion forces and entropic effects are the major determinants of the dissociation equilibria.
    No preview · Article · May 2015 · Organometallics
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    ABSTRACT: The reaction mechanism and origin of regioselectivity of (2 + 2) cycloadditions of benzyne to endohedral metallofullerenes M3N@C80 (M = Sc, Y) were investigated with density functional calculations. The reaction was demonstrated to follow a diradical mechanism rather than a carbene mechanism, in which the formation of the diradical intermediate is the rate-determining step. Through rotation of benzyne moiety on the fullerene surface, the diradical intermediate on 566 site could isomerize to two new diradical intermediates which result in two distinct (5,6) and (6,6) benzoadducts respectively. However, the diradical intermediate on 666 site only produces the (6,6) benzoadduct. The nature of the endohedral cluster not only influences the regioselectivity, but also determines the cycloadduct geometry. For Sc3N@C80, the (5,6) benzoadduct is preferred kinetically and thermodynamically, whereas in the case of Y3N@C80, both (5,6) and (6,6) benzoadducts are favorable. In contrast to closed-cage benzoadducts of Sc3N@C80, Y3N@C80 affords open-cage benzoadducts, making it the first example that the endohedral cluster could alter cycloadducts from the closed cage to open cage. With further analysis, it is revealed that the origin of regioselectivity results from the local strain energy of the fullerene cage.
    No preview · Article · May 2015 · Journal of the American Chemical Society
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    ABSTRACT: The water-dimer thermodynamics is recomputed, combining the dimerization potential-energy change evaluated from the G3 theory (–5.142 kcal/mol, almost equal to the recently observed term) and the an harmonic partition functions from the MP2 = FC/6-3111 + +G** approach. The combined treatment reproduces the observed terms basically within possible experimental errors. Thus, the calculated thermodynamic characteristics are recommended for wider use and applied to the issue of temperature increase of clustering degree in the saturated steam, confirming the temperature enhancement also in the an harmonic regime and hence pointing out higher-temperature region to spectroscopy interest and also for the water-dimer encapsulations into fullerene cages like (H2O)2 @C60 and (H2O)2 @C84. The results also have some significance for the atmospheric greenhouse effect.
    No preview · Article · Apr 2015 · Journal of Computational and Theoretical Nanoscience
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    Full-text · Dataset · Jan 2015
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    ABSTRACT: The first dianionic compounds bearing a bond between two pentacoordinated germanium atoms have been synthesized in a stable form as candidates for a core unit to construct unprecedented structures in group 14 element chemistry. X-ray crystallographic analysis and computational study indicated the single-bond character of the Ge–Ge bond. They were reversibly converted to the anionic and neutral Ge–Ge-bonded compounds while maintaining the coordination number of the germanium atoms. The interconversion features changes in structures around the germanium atoms, including changes from a staggered conformation of the Ge–O bonds to a parallel conformation.
    No preview · Article · Jan 2015 · Organometallics
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    ABSTRACT: A 1,2-digermabenzene bearing bulky substituents on its two germanium atoms was successfully synthesized and isolated as a stable, crystalline compound via the reaction of a digermyne precursor with 2 equiv of acetylene. Even though its molecular structure, which was revealed by X-ray crystallographic analysis, showed a trans-bent geometry for the Ge-Ge moiety, theoretical calculations suggested substantial levels of aromaticity.
    No preview · Article · Jan 2015 · Organometallics

Publication Stats

17k Citations
3,226.89 Total Impact Points

Institutions

  • 2012-2015
    • Huazhong University of Science and Technology
      • State Key Laboratory of Material Processing and Die & Mould Technology
      Wu-han-shih, Hubei, China
    • Fukui Institute for Fundamental Chemistry
      Kioto, Kyōto, Japan
    • Saitama University
      • Department of Chemistry
      Saitama, Saitama, Japan
  • 2010-2015
    • Kyoto University
      • • Fukui Institute for Fundamental Chemistry
      • • Institute for Chemical Research
      Kioto, Kyoto, Japan
    • Tohoku University
      • Department of Chemistry
      Japan
    • Friedrich-Alexander-University of Erlangen-Nürnberg
      • Department of Chemistry and Pharmacy
      Erlangen, Bavaria, Germany
    • Nagoya University
      • Department of Chemistry
      Nagoya, Aichi, Japan
    • National Chung Cheng University
      Chia-i-hsien, Taiwan, Taiwan
  • 2014
    • University of California, Davis
      • Department of Chemistry
      Davis, California, United States
    • Heilongjiang University
      • School of Chemistry and Materials Science
      Charbin, Heilongjiang Sheng, China
  • 1990-2014
    • University of Tsukuba
      • Graduate School of Pure and Applied Sciences
      Tsukuba, Ibaraki, Japan
  • 2008-2013
    • National Institutes Of Natural Sciences
      Edo, Tōkyō, Japan
  • 2006-2013
    • Tokyo Gakugei University
      Koganei, Tōkyō, Japan
    • The Graduate University for Advanced Studies
      • Department of Structural Molecular Science
      Миура, Kanagawa, Japan
  • 2011
    • Osaka Prefecture University
      Sakai, Ōsaka, Japan
  • 2001-2010
    • Niigata University
      • Graduate School of Science and Technology
      Niahi-niigata, Niigata, Japan
  • 2007
    • Nankai University
      • Institute of New Energy Material Chemistry
      T’ien-ching-shih, Tianjin Shi, China
    • Charles University in Prague
      • Department of Physical and Macromolecular Chemistry
      Praha, Praha, Czech Republic
    • Peking University
      • Department of Chemistry
      Peping, Beijing, China
  • 2001-2006
    • Academia Sinica
      • Institute of Chemistry
      Taipei, Taipei, Taiwan
  • 1995-2006
    • Tokyo Metropolitan University
      • Department of Chemistry
      Edo, Tōkyō, Japan
  • 2004
    • Athens State University
      Athens, Alabama, United States
  • 2002
    • Waseda University
      Edo, Tōkyō, Japan
    • Institute for Molecular Science
      Okazaki, Aichi, Japan
    • Hiroshima University
      • Division of Chemistry
      Hiroshima-shi, Hiroshima-ken, Japan
  • 1981-1995
    • Yokohama National University
      Yokohama, Kanagawa, Japan
  • 1993
    • The University of Tokyo
      • Department of Chemistry
      Edo, Tōkyō, Japan
  • 1989
    • Dalmia Institute of Scientific and Industrial Research
      Sundergarh, Orissa, India