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化学学报
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化学学报 ›› 2005, Vol. 63 ›› Issue (10): 897-902. 上一篇    下一篇

研究论文

全氟烷基磺酸酯C—O键断裂的同面SN2反应

郭丽1，虞忠衡*1，朱士正2，陈庆云2   

  1. (1中国科学院化学研究所分子动态和稳态国家重点实验室 北京 100080)
    (2中国科学院上海有机化学研究所 上海 200032)
  • 投稿日期:2004-09-13 修回日期:2005-01-25 发布日期:2010-12-10
  • 通讯作者: 虞忠衡

Front-Side SN2 Reaction, CF3SO3CF2CF3＋F－, Leading to the C—O Cleavage

GUO Li1, YU Zhong-Heng*1, ZHU Shi-Zheng2, CHEN Qing-Yun2   

  1. (1 State Key Laboratory for Structural Chemistry of Unstable & Stable Species, Institute of Chemistry,
    Chinese Academy of Sciences, Beijing 100080)
    (2 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032)
  • Received:2004-09-13 Revised:2005-01-25 Published:2010-12-10
  • Contact: YU Zhong-Heng

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用密度泛函理论研究了CF3SO3CF2CF3＋F－的碳氧键断裂反应的机理. 首先, 用DFT方法优化了反应物、中间体、过渡态、产物的平衡构型, 分析了碳氧键断裂反应的势能面变化. 发现在SN2反应机理中, 除了S—O断裂SN2反应外, 引起C—O键断裂的同面进攻也是一个可能的反应途径. 理论计算表明, 最终反应的产物是受热力学控制的, S—O键的断裂绝对地优于C—O的断裂. 因此, C—O断裂的同面机理虽然是可能的, 但却难以被实验观察到. 本文还讨论了端基 —F3在同面SN2反应中的邻位效应, 以及基组对这个效应的影响.

关键词: 反应机理, DFT方法, 全氟磺酸酯, 同面SN2反应

The front-side SN2 reaction, CF3SO3CF2CF3＋F－, leading to the C—O cleavage was studied using DFT. The reactant complex, transition state, product complex and products, including their vibration frequencies, were optimized and calculated at B3LYP/6-311G** level. The potential energy surface for the front-side SN2 reaction was investigated, showing that the front-side SN2 mechanism is possible. However, as shown by computation, the products are thermodynamically controlled, and the S—O cleavage is predominates over the C—O cleavage. As a result, it is difficult for the products resulting from the C—O cleavage to be detected experimentally. Meanwhile, the neighboring effect of the —CF3 group on the front-side SN2 mechanism was found.

Key words: reaction mechanism, DFT method, perfluorosulfonate, the front-side SN2 reaction