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Studies on Energy Transfer with Spin Polarization Conservation in organic Photochemical Reactions

Research Project

Project/Area Number 02453002
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 物理化学一般
Research InstitutionTohoku University

Principal Investigator

IKEGAMI Yusaku  Tohoku University, institute for Chemical Reaction Science, Professor, 反応化学研究所, 教授 (60006294)

Co-Investigator(Kenkyū-buntansha) IKOMA Tadaaki  Tohoku University, institute for Chemical Reaction Science. Research Associate, 反応化学研究所, 助手 (10212804)
AKIYAMA Kimio  Tohoku University, Institute for Chemical Reaction Science, Research Associate, 反応化学研究所, 助手 (10167851)
Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥4,800,000 (Direct Cost: ¥4,800,000)
KeywordsTime-Resolved EPR Spectroscopy / Energy Transfer with Spin Polarization Conservation / Intermolecular Energy Transfer / Pyridinyl Radicals / Aromatic Ketone / Photochemical Reaction / 光化学反応 / トロポン / 励起三重項状態 / スピン分極 / エネルギ-移動 / 時間分解EPR / 三重項状態
Research Abstract

The studies have been carried out to clarify the spin polarization conservation during triplet-triplet energy transfer in fluid solution. This phenomenon first demonstrated by us in 1984 for the photochemical cleavage of the dimers of neutral pyridinyl radicals is important to interpret molecular energy transfer mechanism. The following results have been obtained.
1. Monomer-dimer equilibrium of pyridinyl radicals and its photochemistry. Neutral pyridinyl radicals are substantially in equilibrium with their dimers and the dimers show photochemical cleavage producing the radicals. Time-resolved EPR studies on the initial process disclosed the precursor of photolysis to be the singlet excited state. On the other hand, in the presence of an appropriate triplet sensitizer, triplet-triplet energy transfer with spin polarization conservation occurred leading to the generation of the radical through excited triplet state. Detailed studies on many pyridinyl dimers established a characteristic chemistry of pyridinyl radicals.
2. Spin polarization conservation during the intramolecular triplet-triplet energy transfer. This phenomenon was successfully demonstrated by the measurements of transient triplet EPR spectra for two types of spiran compounds containing energy-donor and acceptor moieties. Spin alignment is conserved in the molecular frame and high field approximation can not explain the spin polarization pattern of the specatra.
3. Other photochemical processes. The photochemical initial processes have been clarified for the following titles : (1) CIDEP studies on radicals produced from photochemical reactions of some aromatic carbonyl compounds ; (2) Time-resolved EPR studies on photochemical hydrogen abstraction reactions of 4-substituted pyridines ; (3) Time-resolved EPR study on the excited triplet state of non-phosphorescent tropone.

Report

(3 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (19 results)

All Other

All Publications (19 results)

  • [Publications] K.Akiyama A.Kaneko S.Tero-Kubota Y.Ikegami: "Spin Polarization Conservation during Triplet-Triplet Energy Transfer in Fluid Solution as Studied by Time-resolved ESR Spectroscopy" J.Am.Chem.Soc.112. 3297-3301 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T.Ikoma K.Akiyama S.Tero-Kubota Y.Ikegami: "CIDEP Studies on Radicals Produced from Photochemical Reactions of Some Aromatic Carbonyl Compounds" Chem.Lett.1491-1494 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] S.Tero-Kubota K.Akiyama T.Ikoma Y.Ikegami: "Time-resolved EPR Studies on the Photochemical Hydrogen Abstraction Reactions and the Excited Triplet States of 4-Substituted Pyridines" J.Phys.Chem. 95. 766-770 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T.Ikoma K.Akiyama S.Tero-Kubota Y.Ikegami: "Time-resolved EPR Study on the Excited Triplet State of Non-phosphorescent Tropone" J.Phys.Chem.95. 7119-7121 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] S.Tero-Kubota,T.Noguchi A.Katsuki,K.Akiyama Y.Ikegami: "Time-resolved EPR Spectra of the Excited Triplet States Generated from the Photoinduced Intramolecular Proton Transfer and from the Direct Excitation Reaction in 2-(N-Phenylacetimidoyl)-l-naphthol" Chem.Phys.Lett.187. 423-426 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 池上 雄作,手老 省三,秋山 公男: "(総説)ピリジニルラジカルのモノマ-ーダイマ-平衡とその光化学" 東北大学反応化学研究所報告. 1. 23-43 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] S.Tero-Kubota K.Akiyama F.Shoji Y.Ikegami: "The Excited Triplet State Generated from the Excited State Intramolecular Proton Transfer in 2-(2'-Hydroxyphenyl)benzothiazole" J.Chem.Soc.,Chem.Commun.(1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] K.Akiyama S.Tero-Kubota Y.Ikegami: "Spin Polarization Transfer during the Intramolecular Triplet-Triplet Energy Transfer under External Magnetic Field in a Rigid Matrix as Studied by Time-resolved EPR Spectroscopy" J.Am.Chem.Soc.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T.Ikoma,K.Akiyama,S.TeroーKubota,Y.Ikegami: "Timeーresolved EPR Study on the Excited Triplet State of Nonーphosphorescent Tropone" J.Phys.Chem.95. 7119-7121 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] S.TeroーKubota,T.Noguchi,A.Katsuki,K.Akiyama,Y.Ikegami: "Timeーresolved EPR Spectra of the Excited Triplet States Generated from the Photoinduced Intramolecular Proton Transfer and from the Direct Excitation Reactions in 2ー(NーPhenylacetimidoyl)ー1ーnaphthol" Chem.Phys.Lett.187. 423-426 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 池上 雄作,手老 省三,秋山 公男: "(総説)ピリビニルラジカルのモノマ-ーダイマー平衡とその光化学" 東北大学反応化学研究所報告. 1. 23-43 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] S.TeroーKubota;K.Akiyama;F.Shoji;Y.Ikegami: "The Excited TriPlet State Generated from the Excited State Intraーmolecular Proton Transfer in 2ー(2'ーHydroxyphenl)benzothiazole" J.Chem.Soc.,Chem.Commun. (1992)

    • Related Report
      1991 Annual Research Report
  • [Publications] K.Akiyama;S.TeroーKubota;Y.Ikegami: "Spin Polarization Transfer during the Intramolecular TripletーTriplet Energy Transfer under External Magnetic Field in a rigid Matrix as Studied by TimeーResolved EPR Spectroscopy"

    • Related Report
      1991 Annual Research Report
  • [Publications] K.Akiyama A.Kaneko S.TeroーKubota Y.Ikegami: "Spin Polarization Conservation during TripletーTriplet Energy Transfer in Fluid Solution As Studied by TimeーResolved ESR Spectroscopy." J.Am.Chem.Soc.112. 3297-3301 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] T.Ikoma K.Akiyama S.TeroーKubota Y.Ikegami: "CIDEP Studies on Radicals Produced from Photochemical Reactions of Some Aromatic Carbonyl Compounds." Chem.Lett.1491-1494 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] S.TeroーKubota K.Akiyama T.Ikoma Y.Ikegami: "TimeーResolved EPR Studies on the Photochemical Hydrogen Abstraction Reactions and the Excited Triplet States of 4ーSubstituted Pyridines." J.Phys.Chem.95. 766-770 (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] T.Hirano,T.Kumagai T.Miyashi,K.Akiyama Y.Ikegami: "Photoreactions of Benzyhydrilidenequadricyclane and Quadricyclanone:A New Route to Trimethylenemethane and Oxyallyl Intermediate." J.Org.Chem.56. (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] K.Takahashi T.Suzuki K.Akiyama Y.Ikegami: "Synthesis and Characterization of Novel pーTerphenoquinone Analogues Extended by DihydrothiophenediylideneーInsertion into pーDiphenoquinone." J.Am.Chem.Soc.113. (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] K.Akiyama S.TeroーKubota Y.Ikegami: "Spin Polarization Transfer during the Intramolecular TripletーTriplet Energy Transfer under External Magnetic Field in a Rigid Matrix as Studied by TimeーResolved EPR Spectroscopy." J.Am.Chem.SoC.

    • Related Report
      1990 Annual Research Report

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Published: 1990-04-01   Modified: 2016-04-21  

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