碳氟键均裂解离能的密度泛函理论研究

Density Functional Theory Study on Homolytic Bond Dissociation Enthalpies of Carbon-Fluorine Bond

运用6种密度泛函方法(B3LYP,B3P86,B3PW91,PBE1PBE,MPW1B95,MPW1K)对15个含氟有机化合物的碳氟键均裂解离能进行理论计算,得到的理论值与实验值比较,发现B3P86方法用于碳氟键均裂解离能的计算相对可靠.使用验证后的理论方法对含氟杂环有机化合物和卤氟烃中的碳氟键均裂解离能进行了预测和分析,并进一步讨论了α-取代基效应以及Hammett型取代基效应对碳氟键均裂解离能的影响.

Six density functional methods （B3LYP, B3P86, B3PW91, PBE1PBE, MPW1B95, MPW1K） were employed to calculate C-F homolytic bond dissociation enthalpies （BDEs） of 15 fluorine containing organic compounds. Theoretical BDEs were compared with the available experimental values to confirm the suitability of these methods. It was found that B3P86 method has a comparable reliable performance. The BDEs of fluorine containing heterocycles and fluorochlorohydrocarbons were computed by carefully benchmarked method. In addition, the a-substituent effect and Hammett relationship were discussed.