大学化学 >> 2017, Vol. 32 >> Issue (8): 60-65.doi: 10.3866/PKU.DXHX201701017

师生笔谈 上一篇    下一篇

碳负离子重排的DFT计算研究

王文峰*(),袁耀锋,李俊篯   

  • 发布日期:2017-08-15
  • 通讯作者: 王文峰 E-mail:wangwf@fzu.edu.cn
  • 基金资助:
    福建省自然科学基金(2017J01578);福州大学高等教育教学改革工程项目

A DFT Study on the Rearrangement of Carbanion

Wen-Feng WANG*(),Yao-Feng YUAN,Jun-Qian LI   

  • Published:2017-08-15
  • Contact: Wen-Feng WANG E-mail:wangwf@fzu.edu.cn
  • Supported by:
    福建省自然科学基金(2017J01578);福州大学高等教育教学改革工程项目

摘要:

采用密度泛函方法计算了碳负离子1,2-迁移和1,4-迁移两个反应的过渡态的分子轨道,发现在过渡态中迁移原子携带正电荷,剩余部分则形成双碳负离子。在1,2-迁移过渡态中,剩余的双碳负离子的HOMO位相与迁移原子的LUMO位相不匹配。但在1,4-迁移过渡态中,剩余的双碳负离子的HOMO位相与迁移原子的LUMO位相匹配。所以碳负离子的1,2-迁移是轨道对称性禁阻的反应,而1,4-迁移则是轨道对称性允许的反应。本文的计算可以为我国高等有机化学教学提供良好参考。

关键词: 碳负离子, 重排, 轨道对称性, 化学计算

Abstract:

The molecular orbitals of transition states of 1, 2-shift and 1, 4-shift of carbanion were calculated using the density functional theory (DFT) method. It was found that the migration atom carried positive charge and the rest of the carbanion became a double carbanion. In the transition state of 1, 2-shift, the phase of HOMO of the double carbanion doesn't match that of LUMO of the migration atom. However, in the transition state of 1, 4-shift, the phase of HOMO of the double carbanion matches that of LUMO of the migration atom. So the 1, 2-shift of carbanion is an orbital symmetry prohibited reaction and the 1, 4-shift of carbanion is an orbital symmetry permitted reaction. The calculation in this paper can afford a valuable reference for the teaching of advanced organic chemistry.

Key words: Carbanion, Rearrangement, Orbital symmetry, Chemical calculation

MSC2000: 

  • G64