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2002 Fiscal Year Final Research Report Summary

X-Ray Crystal Structure Analyses of Unstable Triplet Carbenes and Nitrenes and Comparison with their Reactivities

Research Project

Project/Area Number 13440174
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Physical chemistry
Research InstitutionTokyo Institute of Technology

Principal Investigator

OHASHI Yuji  Tokyo Institute of Technology, Deppartment of Chemistry and Materials Science, Professor, 大学院・理工学研究科, 教授 (40016118)

Co-Investigator(Kenkyū-buntansha) SEKINE Akiko  Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 助手 (40226650)
UEKUSA Hidehiro  Tokyo Institute of Technology, Associate Professor, 大学院・理工学研究科, 助教授 (60242260)
Project Period (FY) 2001 – 2002
KeywordsTriplet Carbene / Triplet Nitrene / X-ray Analysis / Unstable Intermediates / Structure of Excites State / Excite state of Platinum Complex / Diazomethane Derivatives / Azido Compounds
Research Abstract

In order to understand the mechanism of chemical reactions, it is essential to obtain the reaction intermediates and to analyze their characteristics. Although the spectroscopic studies have been made clear the energy change of the excited molecules in the time scale of a few femtosecond, the structures of the excited molecule have been obscure till now, since it has been considered to be impossible to trap the excited molecules in a crystalline lattice and to analyze the structures by X-rays. In the present work, we intended to analyze the structures of unstable species such as triplet carbenes and nitrenes. The crystal of the reactant molecule, diazomethane or phenylazide, was cooled below 80 K on the diffractometer using the nitrogen-gas-flow method and was exposed to the high-pressure mercury lamp using a guide tube. The diffraction data were collected after the irradiation at low temperatures. In a difference Fourier map, the new peaks appeared, which were assigned the produced ca … More rbene or nitrene, although only 10% reactant molecules were converted to the unstable species. The structures are in good agreement with those obtained from the theoretical calculation. For the nitrene, it was difficult to obtain the precise structure, since the produced nitrene overlapped on the reactant molecule in the crystalline lattice. The host-guest complex was produced using dibenzylamine as a host. The irradiated crystal was analyzed by the vacuum camera set up at Spring-8. The precise structure of the nitrene was obtained from the host-guest complex. Moreover, the crystal of a platinum complex was exposed to a xenon lamp at 80K. The diffraction data before and during the irradiation were collected and both of the structures were analyzed. The lattice constant clearly changed during the irradiation. The structure during the irradiation clearly indicated that the Pt-Pt distance is shortened at the excited state in accordance with the molecular orbital theory. A11 the above results suggest that the X-ray crystallography will play an important role in analyzing the unstable species in near future. Less

  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] Masaki Kawano, Katsuyuki Hirai, Hideo Tomioka, Yuji Ohashi: "Structure Analysis of a Transient Triplet Carbene Trapped in a Crystal"J.Am.Chem.Soc.. 123. 6904-6908 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Pance Naumov, Akiko Sekine, Hidehiro Uekusa, Yuji Ohashi: "Structure of the Photocolored 2-(2',4'-Dinitrobenzyl)pyridine Crystal : Two Photon Induced Solid-State Proton Transfer with Minor Structural perturbation"J.Am.Chem.Soc.. 124. 8540-8541 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Masaki Kawano, Yoshiki Ozawa, Koutatsu Matsubara, Hidekazu Imabayashi, Minoru Mitsumi, Koshiro Toriumi, Yuji Ohashi: "Synchrotron Radiation Structure Analyses of the Light-induced Radical Pair of a Hexaarylbiimidazolyl Derivative. Origin of the Spin-Multiplicity Change"Chem.Lett.. 2002. 1130-1131 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Nobuhiro Yasuda, Masaki Kanazawa, Hidehiro Uekusa, Yuji Ohashi: "Excited-state Structure of a Platinum Complex by X-ray Analysis"Chem.Lett.. 2002. 1132-1133 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoshiki Ozawa, Madoka Terashima, Minoru Mitsumi, Koshiro Toriumi, Nobuhiro Yasuda, Hidehiro Uekusa, Yuji Ohashi: "Photoexcited Crystallography of Diplatinum Complex by Multi-exposure IP Method"Chem.Lett.. 2003. 62-63 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Terufumi Takayama, Masaki Kawano, Hidehiro Uekusa, Yuji Ohashi, Tadashi Sugawara: "Crystalline-State Photoreaction of 2-Nitrophenylazide -Direct Observation of Hetero-ring Formation by X-ray Crystallography"Helv.Chim.Acta. (印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 大橋裕二: "励起分子のX線構造解析"未来材料. 2. 77-80 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 大橋裕二: "分子の変化を捉えるX線構造解析"触媒(触媒学会誌). 44・8. 625-630 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yuji Ohashi: "Racemic-to-Chiral Transformation and Chrality Inversion Process in Cobaloxime Complex Crystals Only by Photoirradiation"(Marcel Dekker, Inc.)Molecular and Supramolecular Photochemistry(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Masaki Kawano, Katsuyuki Hirai, Hideo Tomioka and Yuji Ohashi: "Structure Analysis of a Transient Triplet Carbene Trapped in a Crystal"J. Am. Chem. Soc.. 123. 6904-6908 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Pance Naumov, Akiko Sekine, Hidehiro Uekusa, and Yuji Ohashi: "Structure of the Photocolored 2-(2', 4'-Dinitrobenzyl)pyridine Crystal : Two Photon Induced Solid-State Proton Transfer with Minor Structural perturbation"J. Am. Chem. Soc.. 124. 8540-8541 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Masaki Kawano, Yoshiki Ozawa, Koutatsu Matsubara, Hidekazu Imabayashi, Minoru Mitsumi, Kshiro Toriumi and Yuji Ohashi: "Synchrotron Radiation Structure Analyses of the Light-induced Radical Pair of a Hexaarylbiimidazolyl Derivative. Origin of the Spin-Multiplicity Change"Chem. Lett.. 2002. 1130-1131 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Nobuhiro Yasuda, Masaki Kanazawa, Hidehiro Uekusa and Yuji Ohashi: "Excited-state Structure of a Platinum Complex by X-ray Analysis"Chem. Lett.. 2002. 1132-1133 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshiki Ozawa, Madoka Terashima, Minoru Mitsumi, Koshiro Toriumi, Nobuhiro Yasuda, Hidehiro Uekusa and Yuji Ohashi: "Photoexcited Crystallography of Diplatinum Complex by Multi-exposure IP Method"Chem. Lett.. 2003. 62-63 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Terufumi Takayama, Masaki Kawano, Hidehiro Uekusa, Yuji Ohashi and Tadashi Sugawara: Helv. Chim. Acta. in press. (2003)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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