大学化学 >> 2023, Vol. 38 >> Issue (2): 197-206.doi: 10.3866/PKU.DXHX202205027

化学实验 上一篇    下一篇

烯丙基正离子旋转异构反应的计算化学实验设计

王亚妮, 张学鹏()   

  • 收稿日期:2022-05-08 录用日期:2022-06-27 发布日期:2022-07-07
  • 通讯作者: 张学鹏 E-mail:zhangxp@snnu.edu.cn
  • 基金资助:
    国家自然科学基金(22003036)

Investigations on Allyl Cation Rotational Isomerism: A Computational Experiment Design

Ya'ni Wang, Xue-Peng Zhang()   

  • Received:2022-05-08 Accepted:2022-06-27 Published:2022-07-07
  • Contact: Xue-Peng Zhang E-mail:zhangxp@snnu.edu.cn

摘要:

设计了一个面向高年级本科生或低年级研究生的计算化学探索实验,即利用密度泛函理论(DFT)计算烯丙基正离子的旋转异构反应。该实验设计了反应物结构优化、过渡态寻找、内禀反应坐标建立等过程,可以较为全面地帮助学生了解计算化学的基本概念与操作,加深对分子微观结构的感知以及对过渡态理论中“旧键即将断裂,新键即将形成”概念的理解。本实验通过旋转异构反应的势能面的构建,也可以帮助学生认识反应热力学和动力学的差别。通过进一步的电荷布居分析以及前线轨道分析,可以帮助学生直观地学习并理解分子的电子结构以及反应活性位点概念。

关键词: 烯丙基正离子, 旋转异构, 密度泛函理论, 反应势能面, 实验设计

Abstract:

In this study, a computational chemistry exploration experiment for senior undergraduate or beginning graduate students is designed. The rotational isomerization reaction of an allyl cation is investigated using density functional theory (DFT) calculations. The theoretical experiment involves molecular geometry optimization, transition state location, and establishment of intrinsic reaction coordinates (IRCs). This design can help students understand the basic concepts and operations of computational chemistry. Furthermore, the concepts of molecular microstructures and the notion of "old bonds are about to break and new bonds are about to form" in the transition state theory are discussed. This experiment will also aid the understanding of the differences between reaction thermodynamics and kinetics through the construction of potential energy surfaces. Further investigations of charge population analysis and frontier orbital analysis will aid the understanding of electronic structures of molecules as well as the concept of reaction reactive sites.

Key words: Allyl cation, Rotational isomerism, Density functional theory, Potential energy surface, Experimental design