物理化学学报 >> 1992, Vol. 8 >> Issue (02): 181-185.doi: 10.3866/PKU.WHXB19920208

研究论文 上一篇    下一篇

咪唑与单线态氧(1O2)1,2-环加成反应的理论研究

马思渝; 丁燕波; 傅孝愿   

  1. 北京师范大学化学系,北京 100875
  • 收稿日期:1990-10-04 修回日期:1991-02-08 发布日期:1992-04-15
  • 通讯作者: 傅孝愿

Theoretical Studies on the 1,2-Cycloaddition Reaction of Singlet Molecular Oxygen (1O2) with Imidazole

Ma Si-Yu; Ding Yan-Bo; Fu Xiao-Yuan   

  1. Department of Chemistry, Beijing Normal University, Beijing 100875
  • Received:1990-10-04 Revised:1991-02-08 Published:1992-04-15
  • Contact: Fu Xiao-Yuan

摘要: 采用较新的半经验分子轨道方法Austin Model 1(简称AM1方法), 辅以Berny梯度优化方法, 对单线态氧(~1O_2)与咪唑的1,2-环加成反应,进行了理论研究。计算获得实验尚未检测到的4,5-二氧环丁烷(4,5-dioxetane)的结构, 并在反应势能面上找到单重态双自由基中间体及通过该中间体的两步反应的过渡态。通过对过渡态的结构特征、虚振动方向以及对反应过程的电荷分布情况、轨道相互作用等的分析, 说明该反应是经由单重态双自由基中间体的分步反应。两步反应的活化势垒分别为39.2 kJ·mol~(-1)和150.5 kJ·mol~(-1)。

关键词: 咪唑, 单线态氧, 双自由基, 1,2-环加成反应

Abstract: The 1,2-cycloaddition reaction mechanism of singlet molecular oxygen ~1O_2 with imidazole has been investigated by semiempirical molecular orbital AM1 method and energy gradient technique. The calculated results show that the mentioned reaction is a stepwise reaction via a diradical intermediate. The barrier height of the first step reaction is 39.2 kJ·mol~(-1) while the second step reaction is 150.5 kJ·mol~(-1). The second step reaction is the rate determining step.

Key words: Imidazole, Singlet oxygen, Diradical, 1,2-cycloaddition reaction