高等学校化学学报

高等学校化学学报 ›› 2005, Vol. 26 ›› Issue (4): 747.

• 研究论文 • 上一篇    下一篇

2-甲基噻吩光异构化成3-甲基噻吩的理论研究

王艳霞1, 陈益山2, 叶松1   

  1. 1. 云南大学化学材料工程学院化学系, 昆明 650091;
    2. 曲靖师范学院化学系, 曲靖 655000
  • 收稿日期:2004-03-01 出版日期:2005-04-10 发布日期:2005-04-10
  • 通讯作者: 叶　松(1945年出生),男,教授,主要从事量子化学研究.E-mail:songye@ynu.edu.cn E-mail:songye@ynu.edu.cn
  • 基金资助:

    云南省科技厅自然科学基金(批准号:2003A0003M)资助.

Theoretical Study of the Photoisomerization of 2-Methylthiophene to 3-Methylthiophene

WANG Yan-Xia1, CHEN Yi-Shan2, YE Song1   

  1. 1. Department of Chemistry, School of Chemistry and Material Engineering, Yinnan University, Kunming 650091, China;
    2. Department of Chemistry, Qujing Normal University, Qujing 655000, China
  • Received:2004-03-01 Online:2005-04-10 Published:2005-04-10

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被引次数

4

摘要： 用CASSCF方法以6-31G基组研究了2-甲基噻吩光异构化为3-甲基噻吩的光化学反应和基态(S0)及三重激发态(T1)的相关势能面.反应主要发生在三重态(T1)上,其间经历了两个双自由基,1个三元环中间体及4个过渡态.沿着反应路径找到了2个T1/S0势能面交叉点,其结构都类似于双自由基.在第二个T1/S0势能面交叉点附近由T1向S0的系间窜越(ISC)最为有利.

关键词: 2-甲基噻吩, 3-甲基噻吩, CASSCF, 势能面交叉点, 反应路径, 光异构化反应

Abstract: The photoisomerization of 2-methylthiophene to 3-methylthiophene was studied at the CASSCF level with a 6-31G* basis set. The reaction channels on the ground state(S0) and excited state(T1) were investigated. The reaction proceeds via two diradical intermediates, one intermediate product and four transitions states on the T1 surface. The two-diradical T1/S0 intersystem crossing points were located along the reaction path. It is most likely that the intersystem crossing from T1 to S0 occurs near the second crossing point because 3-methylthiophene can be formed very easily. Based on the computation we come to the conclusion that the intersystem crossing from T1 to S0 is the rate-determining step in the reaction.

Key words: Methylthiophene, 3-Methylthiophene, CASSCF, Intersystem crossng point, Reaction path, Photoisomerization

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