Studies on Conservation of Spin-Polarization in Hydrogen Atom Transfer Reactions.

氢原子转移反应中自旋极化守恒的研究。

• 批准号: 60470005
• 负责人: OBI Kinichi
• 金额: $ 4.29万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60470005/
• 关键词: triplet benzyl; CIDEP; hydrogen atom transfer reaction; spin-polarization; time-resolved ESR; 三重項-三重項エネルギー移動

The time-resolved ESR technique was applied to obtain molecular constants of triplet states and to elucidate mechanisms of intersystem crossing, triplet-triplet energy transfer, hydrogen atom transfer reaction and etc. Main results obtained are summarized as follows:(1) The <^3n(pi)^*> state of biacetyl: From the spin-polarized ESR signals of the <^3n(pi)^*> state of biacetyl produced directly by the <T_1> <- <S_0> absorption, the sign of the D value is determined to be positive. The marked matrix effect on spin polarization in the <^3n(pi)^*> state is interpreted by the switching of intersystem crossing channel in ethanol and nonpolar solvents.(2) Triplet-triplet energy transfer: Transient spin-polarized ESR spectra of triplet state resulting from triplet-triplet energy transfer were studied in organic matrices at 77 K. The spin-polarized ESR spectra of the acceptor triplet produced by the photosensitization were completely different from those of direct photoexcitation. It is conclud … More ed that the spin polarization of the donor is transferred to the acceptor by triplet-triplet energy transfer and the Zeeman quantum number is conserved, which is interpreted by the exchange mechanism.(3) Spin-polarization transfer in the triplet-doublet system: The interaction between triplet molecules and nitroxide radicals was studied in solution. Spin polarization induced in the radical reflects that of the triplet molecule which is an encounter partner. The spin-polarized ESR signals observed in nitroxide radicals are interpreted in terms of the electron and/or spin exchange mechanisms.(4) Reversal of spin-polarization in the triplet benzyl: The CIDEP signals of produced radicals were observed by the photoirradiation of the benzyl-hydrogen atom donor (aniline, phenoles) systems in benzen solusion. The polarities of the CIDEP signals were reversed by the change of donor and benzyl concentrations and donor reactivities. The revers of spin-polrization was interpreted in terms of the triplet energy transfer between benzyl molecules followed by the structure change of benzyl from nonplanar to planar. Less

本文应用时间分辨ESR技术，获得了三重态的分子常数，并阐明了系间跃迁、三重态-三重态能量转移、氢原子转移反应等机理。主要结果如下：（1）丁二酮的&lt;^3n（pi）^*&gt;态：根据丁二酮的&lt;^3n（pi）^*&gt;态的自旋极化ESR信号<T_1><S_0>，确定了D值的符号为正。在&lt;^3n（pi）^*&gt;态，基体效应对自旋极化的显著影响可以用乙醇和非极性溶剂中的系间交叉通道的转换来解释. (2)三重态-三重态能量转移：在77 K下研究了有机基质中三重态-三重态能量转移的瞬态自旋极化ESR谱。光敏化产生的受体三重态的自旋极化ESR谱与直接光激发的完全不同。结论是， ...更多信息 艾德认为，施主的自旋极化通过三重态-三重态能量转移转移到受主，并且塞曼量子数守恒，这可以用交换机制来解释. (3)三重态-二重态体系中的自旋极化转移：在溶液中研究了三重态分子与氮氧自由基的相互作用。自由基中诱导的自旋极化反映了作为相遇伙伴的三重态分子的自旋极化。氮氧自由基中观察到的自旋极化ESR信号的解释方面的电子和/或自旋交换机制。(4)三重态苄基自旋极化的抑制：通过光照射苄基-氢原子给体（苯胺、酚类）体系，观察到苯溶液中产生的自由基的CIDEP信号。CIDEP信号的极性通过供体和苄基浓度以及供体反应性的改变而逆转。自旋极化的反转可以解释为苄基分子之间的三重态能量转移导致苄基结构由非平面变为平面。少

项目成果

Takashi Imamura, Osamu Onitsuka, Hisao Murai, Kinichi Obi: "Marked Matrix Effect on Spin Polarization of Biacetyl <^3n(pi)^*> State in Low-Temperature Matrices" J. Phys. Chem.89. 4921-4925 (1985)

Takashi Imamura、Osamu Onitsuka、Hisao Murai、Kinichi Obi：“低温基质中双乙酰 <^3n(pi)^*> 状态自旋极化的显着基质效应”J. Phys。

Kazuhiko Shibuya;Hidekazu Nagai;Takashi Imajo;Kinichi Obi;Ikuzo Tanaka: J.Chem.Phys.85. 5061-5067 (1985)

涩谷和彦；永井英和；今城隆；郓津一；田中郁三：J.Chem.Phys.85。

Takashi Imajo;Kazuhiko Shibuya;Kinichi Obi;Ikuzo Tanaka: J.Phys Chem.90. 6006-6011 (1986)

今城隆；涉谷和彦；大比欣一；田中郁三：J.Phys Chem.90。

Takashi Imamura;Osamu Onitsuka;Kinichi Obi: J.Phys.Chem.90. 6741-6744 (1986)

今村隆；鬼冢修；带金一：J.Phys.Chem.90。

Takashi Imajo;Kazuhiko Shibuya;Kinichi Obi: Chem.Phys.Lett.(in press).

Takashi Imajo；Kazuhiko Shibuya；Kinichi Obi：Chem.Phys.Lett.（印刷中）。