Magnetic Field Effects on Photochemical Reaction in Homogeneous Solution

磁场对均质溶液中光化学反应的影响

• 批准号: 12640507
• 负责人: WAKASA Masanobu
• 金额: $ 2.3万
• 依托单位: RIKEN (The Institute of Physical and Chemical Reseach)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640507/
• 关键词: Magnetic Field Effect; Photochemical Reaction; Homogeneous Solution; picosecond laser flash photolysis; Δg mechanism; thiyl radical; Benzophenone; spindynamics; ピコ秒ダイナミクス; 均一系溶媒中; 硫黄ラジカルの反応; ラジカル対; スピン変換過程

We have developed a picosecond laser flash photolysis apparatus with a convenient picosecond pulse laser as an excitation light source and a streak camera to measure transient absorptions. The hydrogen abstraction reaction of triplet 4-methoxy-benzophenone with thiophenol at 265 K was reinvestigated with this apparatus under magnetic fields of 0-1.7 T. The magnetic field effects (MFEs) on this reaction were successfully observed with - 1OO ps time-resolution. The decay rate constant of the generated radical pair was found to increase from 3.42 x 1 09 s^<-1> to 4.15 x 10^9 s^<-1> with increasing magnetic field from 0 T to 1.7 T. The observed magnetic field effects can be explained by the Ag mechanism. Using the simple kinetics model with the Ag mechanism, we tentatively obtained the rate constants of the escape process from the pair (k_<esc>) and the T-S spin conversion process (k_<T-S>) at 0 T and 1.7 T to be 1.97 x 109 s^<-1>, 1.45 x 10^9 s^<-1>, and 2.12 x 10^9 s^<-1>, respectively. From these results, this apparatus is found to be simple and useful for studying MFES on the picosecond spin dynamics.

我们研制了一台皮秒激光闪光光解装置，用方便的皮秒脉冲激光作为激发光源，用条纹相机测量瞬时吸收。在0-1.7T磁场下，用该装置重新研究了265K下对甲氧基二苯甲酮与苯硫酚的三重态吸氢反应，并以-100ps的时间分辨率成功地观察到了磁场对该反应的影响。随着磁场从0T增加到1.7T，生成的自由基对的衰变速率常数从3.42×10~(-9)S^~(-1)增大到4.15×10~(9)S^~(-1)~(-1)，观察到的磁场效应可以用Ag机制来解释。利用带有Ag机制的简单动力学模型，我们初步得到了0T和1.7T下逃逸过程和T-S自旋转换过程的速率常数分别为1.97×109 S^-1和1.45×10^9 S^-1和2.12×10^9 S^-1&gt；从这些结果可以看出，该装置对于研究皮秒自旋动力学中的MFE是简单和有用的。

项目成果

I.Morino, M.Wakasa, H.Hayashi: "Magnetic Field Effects on the Hydrogen Abstraction Reaction of Triplet 4-Methoxy-benzophenone with Thiophenol as Studied by a Picosecond Laser Flash......"Mol. Phys.. (In press). (2002)

I.Morino、M.Wakasa、H.Hayashi：“通过皮秒激光闪光研究磁场对三线态 4-甲氧基-二苯甲酮与苯硫酚的夺氢反应的影响......”Mol。

M.Wakasa,H.Hayashi: "Magnetic Field Effects on the Dynamic Behavior of a Radical Pair as Studied by a Sub-nanosecond Laser Flash Photolysis Technique"Chem.Phys.Lett.. 327. 343-350 (2000)

M.Wakasa,H.Hayashi：“亚纳秒激光闪光光解技术研究的磁场对自由基对动态行为的影响”Chem.Phys.Lett.. 327. 343-350 (2000)

M.Wakasa.H.Hayashi: "Re-examination of the Magnetic Field Effects on the Thermal Reactions of Benzyl and Pentafluorobenzyl Halides with n-Butyllithium in Hexane"Mol. Phys.. (In press). (2002)

M.Wakasa.H.Hayashi：“磁场对苄基和五氟苄基卤化物与正丁基锂在己烷中热反应的影响的重新检验”Mol。

H.Adachi,H.Sonoki,M.Hoshino,M.Wakasa,H.Hayashi, et al.: "Photodissociation of Nitric Oxide from Nitrosyl Metalloporphyrins in Micellar Solutions"J.Phys.Chem.. 105. 392-398 (2001)

H.Adachi、H.Sonoki、M.Hoshino、M.Wakasa、H.Hayashi 等人：“胶束溶液中亚硝基金属卟啉中一氧化氮的光解离”J.Phys.Chem.. 105. 392-398 (2001)

K.Mochida,T.Kayamori,M.Wakasa,H.Hayashi,M.P.Egorov: "Studies of Photochemical Reactions of 7,8-Digermabicyclo [2.2.2] octadienes by Steady-State and Laser Flash Photolysis Techniques"Organometallics. 19. 3379-3386 (2000)

K.Mochida、T.Kayamori、M.Wakasa、H.Hayashi、M.P.Egorov：“通过稳态和激光闪光光解技术研究 7,8-Digermabicyclo [2.2.2] 辛二烯的光化学反应”有机金属。