Photochemical Reaction of Metal Complexes Studied by Advanced EPR

利用先进 EPR 研究金属配合物的光化学反应

• 批准号: 07044058
• 负责人: YAMAUCHI Seigo
• 金额: $ 3.84万
• 依托单位: Institute of Chemical Reaction Science Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044058/
• 关键词: Pulsed EPR; Multi-Dimension; W-band; Time-Resolved EPR; Nutation; Photoinduced electron Transfer; FT-EPR; Metalloporphyrin; Excited Multiplet; 光化学反応; 電子スピン共鳴; 多次元; 光合成; 金属ポリフィリン; 金属フラーレン

In this study we developed new EPR machines and studied photophysics and photochemistry of metal complexes with these laboratory-made EPR apparatus. The following results were obtained :1) The Fourier transform (FT) EPR machine was constructed by modifying our spin echo system for analyzes of photochemical reactions. The experiments of high time-resolution (10ns) and multi-dimensional modes were made possible with this machine.2) In Mobius' laboratory, the W-band EPR machine was constructed and used both in time-resolved and pulsed modes, which has the higher time-resolution (5ns).3) The electron spin polarization transfer was verified for the firsr time in the triplet-doublet system, where we used excited triplet metalloporphyrins and nitroxide radicals. By means of this technique we measured the spin-lattice relaxation times of radicals and observed the spectra of non-polarized radicals.4) The two-dimensional nutation method was applied for the first time in the transient EPR experiment ; mettalloporphyrin-quinone in micellar system. The photochemical intermediate was separated spectroscopically from the radicals and definitely assigned as an ion pair.5) New microwave-pulse sequences were developed and applied to the study of molecular dynamics of metallofullerenes. Temperature dependence of the signal was examined and analyzed in terms of molecular liblations and spin dynamics.6) Triplet-radical pair systems were constructed with metalloporphyrins ligated by pyridinyl-nitroxied radicals. Two kinds of EPR signals were separeted by the W-band EPR technique and assigned by the two-dimensional nutation technique as those of the excited quartet and doublet states.In addition to these scienfically important results, We succeeded in making acontract between our Laboratory and Department of Physics of Berlin Free University and in holding the international Sendai Symposium twice.

本研究开发了新型EPR装置，并利用这些装置对金属配合物的电子物理和光化学进行了研究。1）通过改进我们的自旋回波系统，建立了用于光化学反应分析的傅里叶变换EPR机。2）在Mobius实验室建立了W波段EPR实验机，并在时间分辨和脉冲模式下进行了实验，具有较高的时间分辨（5 ns）; 3）首次在三重态-二重态系统中验证了电子自旋极化转移，我们使用了激发的三重态金属卟啉和氮氧自由基。首次将二维章动方法应用于瞬态EPR实验中，并对金属卟啉-醌胶束体系进行了研究。光化学中间体从自由基中分离出来，并被明确地指定为离子对。5）开发了新的微波脉冲序列，并将其应用于金属富勒烯的分子动力学研究。从分子解离和自旋动力学的角度分析了信号的温度依赖性。6）用吡啶基氮氧自由基连接金属卟啉构建了三重态自由基对体系。用W波段EPR技术分离出两种EPR信号，用二维章动技术归属为激发四重态和激发二重态的EPR信号，除此之外，我们还成功地与柏林自由大学物理系进行了两次合作，并成功地举办了两次国际仙台会议。

项目成果

N.Okabe: "Electron Spin Relaxation Studies of La@C_<82> in the Solid State by EPR" J.Phy.Chem.10. 251-262 (1996)

N.Okabe：“通过 EPR 对固态 La@C_<82> 进行电子自旋弛豫研究”J.Phy.Chem.10。

R.Hanaishi: "Observation pf Spin-Correlated Radical Pairs via Two-Dimensional EPR Nutation Spectroscopy" J. Chem. Phys.,. 103. 4819-4822 (1995)

R.Hanaishi：“通过二维 EPR 章动光谱观察自旋相关自由基对”J. Chem。

M.Rohrer: "Orieentation-Selected 95 GHz High-Field ENDOR Spectroscopy of Plastoquinone Anion" J.Magn.Reson.Ser A.116. 59-66 (1995)

M.Rohrer：“质体醌阴离子的定向选择 95 GHz 高场 ENDOR 光谱”J.Magn.Reson.Ser A.116。

S.Ohkoshi: "Photodissociation of Bis (S-benzyl-1,2-diphenyl-1,2-ethylenedithiolato) metal Complexes" Inorg.Chem.35. 4569-4574 (1996)

S.Ohkoshi：“双（S-苄基-1,2-二苯基-1,2-亚乙基二硫醇）金属配合物的光解离”Inorg.Chem.35。

R.Hanaishi: "1D and 2D FT-EPR Studies on the Photoinduced Electron Transfer" Bull. Chem. Soc. Jpn.,. 69. 1533-1541 (1996)

R.Hanaishi：“光诱导电子转移的 1D 和 2D FT-EPR 研究”公报。