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1996 Fiscal Year Final Research Report Summary

Photochemistry of radical ions with irradiation of electron and laser pulses

Research Project

Project/Area Number 07455341
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 工業物理化学
Research InstitutionOsaka University

Principal Investigator

MAJIMA Tetsuro  Osaka University, The Institute of Scientific and Industrial Research, Associate Professor, 産業科学研究所, 助教授 (00165698)

Co-Investigator(Kenkyū-buntansha) SAJI Sachiko  Osaka University, The Institute of Scientific and Industrial Research, Research, 産業科学研究所, 助手 (50197844)
ISHIDA Akito  Osaka University, The Institute of Scientific and Industrial Research, Research, 産業科学研究所, 助手 (20184525)
Project Period (FY) 1995 – 1996
KeywordsRadiation chemistry / Photochemistry / Radical ions
Research Abstract

Photophysical and chemical properties of radical ions of aromatic compounds in the excited states have been clarified by a pulse radiolysis-laser flash photolysis combined method. The lifetimes of radical cations and anions of cis- and trans-stibene (c-St and t-St) and radical anions of dicyanoanthracene, phenazine, and anthraquinones in the excited states were measured for the first time and their transient phenomena such as the photoelectron ejection, c-t isomerization, and selective hole and electron transfer quenching of the radical cations and anions in the excited states, respectively, were investigated. In the deactivation of radical cations of c-St in the excited doublet state (c-St^<*+**>), the internal conversion competes with the isomerization to t-St^<*+> in a quantum yield of 0.49, whereas t-St^<*+**> is only deactivated via internal conversion. Lifetimes of t-St^<*+**> and c-St^<*+**> are estimated to be approximately 240 and 120 ps, respectively. The shorter lifetime of … More c-St^<*+**> is attributed to isomerization and conversion to another product via twisting about the central C=C double bond. St radical anions in the excited doublet state (St^<*-**>) undergo unimolecular isomerization from c-St^<*-> to t-St^<*->, photoelectron ejection, and electron transfer to biphenyl added as a quencher. From the selective electron transfer from St^<*-**> to biphenyl (Bp), the lifetimes of c-St^<*-**> and t-St^<*-**> are estimated to be approximately 1.5 and 2.5 ns, respectively. The shorter tau of c-St^<*-**> is attributed to isomerization via twisting about the central C=C double bond. The tau values of c-St^<*-**> and t-St^<*-**> are 1 order of magnitude longer than those of c-St^<*+**> and t-St^<*+**>. Lifetimes of approximately 4 ns are estimated for M^<*-**> (M=dicyanoanthracene, phenazine, and anthraquinones). The shorter lifetimes of 1.0-1.4 ns for methyl and chloro substituents on anthraquinone are explained in terms of internal conversion accelerated by rotatio of the substituents. The energy gap between the excited and ground states of M^<・-> is a singnficant factor for the rate of the internal conversion. A solvated pair of M and quencher^<・-> is suggested as an intermediate in the electron-transfer quenching of M^<*-**> by quencher such as fumaronitile. Less

  • Research Products

    (20 results)

All Other

All Publications (20 results)

  • [Publications] Akito Ishida: "Lifetimes and Transient Phenomena of Stilbene Radical Cations in the Second Doublet Excited State" J. Phys. Chem.99. 10808-10814 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sachiko Tojo: "Remarkable Enhancements of Isomerization and Oxidation of Radical Cations of Stilbene Derivations Induced by Charge-Spin Separation" J. Org. Chem.60. 4684-4685 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Morifumi Fujita: "Lifetimes of radical anions of Dicyanoanthracene, Phenazine, and Anthraquinone in the Excite State From the Selective Electron-transfer Quenching" J. Phys. Chem.100・13. 5382-5387 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tetsuro Majima: "Stilbene Radical Anions in the Excited Doublet State" J. Phys. Chem.100・21. 8913-8919 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tetsuro Majima: "Reactivities of Isomerization, Oxidation, and Dimerization of Radical Cations of Stilbene Derivatives" J. Phys. Chem.100・32. 13615-13623 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tetsuro Majima: "Cis-trans isomerization and Oxidation of Radical Cations of Stilbene Derivatives" J. Org. Chem.61・22. 7793-7800 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tetsuro Majima: "Formation of Dimer Radical Anions of Aromatic Acetylenes During Pulse Radiolysis and γ-Radiolysis" J. Phys. Chem.101. 1048-1055 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 真嶋哲朗: "有機ラジカルイオンの光化学" 放射線化学. 60. 3-16 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tetsuro Majima: "Photochemistry of Organic Radical Ions Using Pulse Radiolysis-Flash Photolysis Combined Method" Mem. Inst. Sci. Ind. Res. Osaka Univ.52. 25-31 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Setsuo Takamuku: "Mechanistic Aspects of Chemical Reactivities of Aromatic Radical Ions in the Ground and Excited States" Mem. Inst. Sci. Ind. Res. Osaka Univ.53(印刷中). (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Akito Ishida, Masayuki Fukui, Hiromitsu Ogawa, Sachiko Tojo, Tetsuro Majima, and Setsuo Takamuku: "Lifetimes and Transient phenomena of stilbene radical cations in the second doublet excited state" J.Phys.Chem.99. 10808-10814 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sachiko Tojo, Kazuhiro Morishima, Akito Ishida, Tetsuro Majima, and Setsuo Takamuku: "Remarkable Enhancements of Isomerization and Oxidation of Radical Cations of Stilbene Derivatives Induced by Charge-Spin Separation" J.Org.Chem.60. 4684-4685 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Morifumi Fujita, Akito Ishida, Tetsuro Majima, and Setsuo Takamuku: "Lifetimes of radical anions of Dicyanoanthracene, Phenazine, and Anthraquinone in the Excite State From the Selective Electron-transfer Quenching" J.Phys.Chem.100-13. 5382-5387 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima, Masayuki Fukui, Akito Ishida, and Setsuo Takamuku: "Stilbene Radical Anions in the Excited Doublet State" J.Phys.Chem.100-21. 8913-8919 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima, Sachiko Tojo, Akito Ishida, and Setsuo Takamuku: "Reactivities of Isomerization, Oxidation, and Dimerization of Radical Cations of Stibene Derivatives" J.Phys.Chem.100-32. 13615-13623 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima, Sachiko Tojo, Akito Ishida, and Setsuo Takamuku: "Cis-trans Isomerization and Oxidation of Radical Cations of Stilbene Derivatives" J.Org.Chem.61-22. 7793-7800 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima, Sachiko Tojo, Akito Ishida, and Setsuo Takamuku: "Formation of Dimer Radical Anions of Aromatic Acetylenes During Pulse Radiolysis and gamma-Radiolysis" J.Phys.Chem.101. 1048-1055 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima: "Photochemistry of Organic Radical Ions" Radiation Chemistry. 60. 3-16 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tetsuro Majima and Setsuo Takamuku: "Photochemistry of Organic Radical Ions Using Pulse Radiolysis-Flash Photolysis Combined Method" Mem.Inst.Sci.Ind.Res.Osaka Univ.52. 25-31 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Setsuo Takamuku, Tetsuro Majima, Akito Ishida, and Sachiko Tojo: "Mechanistic Aspects of Chemical Reactivities of Aromatic Radical Ions in the Ground and Excited States" Mem.Inst.Sci.Ind.Res.Osaka Univ.(in press).

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

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Published: 1999-03-09  

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