氟代苯阳离子的理论研究  

Theoretical Study of Fluorinated Benzene Cations

作　　者：李文佐[1] 黄明宝[1] 

机构地区：[1]中国科学院研究生院化学系,北京100039

出　　处：《化学学报》2004年第9期883-887,M004,共6页Acta Chimica Sinica

基　　金：国家自然科学基金 (Nos.2 0 1 730 56 ;2 0 3330 50 )资助项目

摘　　要：用B3LYP方法及 6 3 11G (d ,p)和 6 3 11+G (d ,p)基组 ,对十二种氟代苯阳离子做了理论研究 ,优化了它们的电子基态的结构 ,计算了对应分子的垂直电离势 (VIP)和绝热电离势 (AIP) .依据Jahn Teller理论 ,计算确定了 1,3 ,5 C6H3 F+ 3 和C6F+ 6离子分别具有C2v( 2 B1 )和D2h( 2 B2g)结构 (对应分子分别为D3h和D6h结构 ) .其余十个离子的构型的对称点群与对应分子相同 ,但构型参数值有明显差别 .自然布居分析计算表明这些离子的正电荷主要分布在与F原子相连的C原子和各H原子上 .B3LYP/6 3 11+G (d ,p)The C6H5F+, o-C6H4F2+ , m-C6H4F2+, p-C6H4F2+, 1, 2, 3-C6H3F3+, 1, 2, 4-C6H3F3+, 1, 3, 5-C6H3F3+, 1,2, 3, 4-C6H2F4+, 1, 2, 3, 5-C6H2F4+, 1, 2, 4, 5-C6H2F4+, C6HF5+ and C6F6+ cations were studied by using the DFT B3LYP method in conjunction with the 6-311G (d, p) and 6-311 + G (d, p) basis sets. The ground-state geometries of these cations were predicted. The 1, 3, 5-C6H3F3+ and C6F6+ ions are the Jahn-Teller active species, and they are predicted to have C-2v and D-2h structures, in contrast with the D-3h and D-6h structures of their parent molecules, respectively. Differences in geometry between the cations and their parent molecules were examined. Natural population analysis calculations for these cations indicate that the positive charge resides mainly at the C atom(s) connecting with the F atom(s) and at the H atoms. The B3LYP calculations with the 6-311 + G (d, p) basis predict vertical and adiabatic ionization potential values of the fluorinated benzene molecules in good agreement with the experimental values.

关 键 词：氟代苯阳离子 绝热电离势 垂直电离势 电子基态 构型参数值 B3LYP 自旋密度分布 自然电荷 密度泛函理论 

分 类 号：O625[理学—有机化学]