物理化学学报 >> 1985, Vol. 1 >> Issue (01): 49-56.doi: 10.3866/PKU.WHXB19850107

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乙叉到乙炔重排反应的反应途径的理论研究

刘若庄; 于建国   

  1. 北京师范大学化学系量子化学研究室
  • 收稿日期:1984-08-10 修回日期:1984-10-10 发布日期:1985-02-15

A THEORETICAL STUDY ON THE REACTION PATH OF THE REARRANGEMENT OF VINYLIDENE TO ACETYLENE

Liu Ruozhuang; Yu Jianguo   

  1. Quantum Chemistry Group; Department of Chemistry; Beijing Normal University
  • Received:1984-08-10 Revised:1984-10-10 Published:1985-02-15

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摘要：

本文用Morokuma提出的数值方案, 基于SCF MO ab initio(STO-3G), 求得了乙叉到乙炔重排反应的内禀反应坐标IRC(Fukui提出的与坐标系无关的反应途径), 并对反应过程中几何构型的改变进行了讨论, 在用MINDD/3方法对诚反应进行研究时, 发现反应过程中有其它中间体存在, 本文也对这种不正确的结果进行了讨论。
本文优化得到的反应物、产物和过渡态几何构型与更精确的理论方法所得的结果定性相符, 用单行列式和CID(考虑所有双激发组态的组态相互作用)所得该反应的位垒分别为123.85和95.81 kJ mol~(-1), 也与更精确方法得到的值相符; 本文还得到了该反应的过渡态的振动频率和正则振动模式。

Abstract:

Recent experiments have indicated that vinylidene is a reaction intermediate when HCI is eliminated from a-chloro olefins in a three center mechanism.Theoretical studies have concentrated on the vinyhdene and its rearrangement to acetylene, i.e. on the reactant, transition state and the product, but not on the reaction path.
In this paper, based on ab initio(STO-3G)SCF MO, the IRC (intrinsic reaction coordinate) of this rearrangement reaction was found out by a numerical method proposed by Morokuma to solve the Fukui′s IRC differential equations. According to the IRC, in the course of the reaction, the reaction energy varies mainly with ∠H_aCC. The change of the relative positions of different atoms in the system along the reaction path has been discussed. ...