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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (20): 2203-2210.    下一篇

研究论文

RN (R＝CH3, CH3CH2)异构化及脱氢反应的量子拓扑研究

李晓艳1,2，孙政1，孟令鹏1，郑世钧*,1   

  1. (1河北师范大学计算量子化学研究所 石家庄 050016)
    (2中国科学院研究生院化学与化学工程学院 北京 100049)
  • 投稿日期:2007-03-08 修回日期:2007-05-17 发布日期:2007-10-28
  • 通讯作者: 郑世钧

Quantum Topological Studies on the Isomerization and H2 Elimination Reaction of RN (R＝CH3, CH3CH2)

LI Xiao-Yan1,2; SUN Zheng1; MENG Ling-Peng1; ZHENG Shi-Jun*,1   

  1. (1 Institute of Computational Quantum Chemistry, College of Chemistry, Hebei Normal University, Shijiazhuang 050016)
    (2 College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing 100049)
  • Received:2007-03-08 Revised:2007-05-17 Published:2007-10-28
  • Contact: ZHENG Shi-Jun

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利用量子化学从头算CASSCF方法在6-311＋G (d, p)基组水平上对单线态和三线态RN (R＝CH3, CH3CH2)异构化反应及RN脱氢反应的微观机理进行了理论研究. 在MP2/6-311＋G (d, p)和CCSD/6-311＋G (d, p)水平上进行了单点能校正. 单态和三态势能面的交叉点(ISC)的存在清楚地说明了基态反应物3RN异构化为基态产物1R'NH (R'＝CH2, CH3CH)的过程. 电子密度拓扑分析显示在整个异构化过程中有两种类型的结构过渡态: 单态反应通道为T型过渡态, 三态反应通道为环状过渡态. 单线态RN脱氢反应通道中“原子-分子键”的存在说明两个H原子是以H2的形式从RN中脱去的.

关键词: 反应机理, 电子密度拓扑分析, 结构过渡态, 原子-分子键

The isomerization reactions of singlet state and triplet state RN (R＝CH3, CH3CH2)→R'NH (R'＝CH2, CH3CH), and hydrogen elimination reactions of RN have been investigated at CASSCF/6-311＋G (d, p) level. The single point energies are obtained at MP2/6-311＋G (d, p) and CCSD/6-311＋G (d, p) levels. The intersystem crossing (ISC) of the singlet and triplet potential surface during the RN (R＝CH3, CH3CH2) isomerization illustrates clearly how the ground-state reactants 3RN (R＝CH3, CH3CH2) transform to ground-state products 1R'NH (R'＝CH2, CH3CH). The topological analysis of electron density shows that there exist two kind of structure transitional structure (STS) in the whole isomerization: a T-shaped conflict STS appears in the singlet isomeration channel and a bifurcation-type ring structure appears in the triplet isomeration channel. The “atom-molecule bond”, which exists in the H2 elimination channel, shows that two hydrogen atoms eliminate from CH3N as a H2 molecule.

Key words: reaction mechanism, electron density of topological analysis, structure transition state, atom-molecule bond