摘要
利用量子化学密度泛函理论B3LYP方法及 6 31G(d ,p)、6 311G(d ,p)、6 31+G(d ,p)和 6 311+G(d ,p)基组对五氟代吡啶、2 ,6 二氟代吡啶和 2 氟代吡啶分子的阳离子进行了计算研究 .B3LYP构型优化和频率分析计算结果表明这三种氟代吡啶阳离子的结构分别具有C2v、C2v和Cs 对称性 ,电子基态分别为2 A2 、2 A2 和2 A″ .对离子和分子的计算构型做了比较 .利用B3LYP方法和不同的基组对这三种阳离子及其分子进行了自然布居分析计算 .用B3LYP方法对这三种阳离子 (自由基 )中的超精细结构进行了计算 ,对五氟代吡啶、2 ,6 二氟代吡啶和2 氟代吡啶分子的垂直电离势和绝热电离势进行了计算 。
Cations of fluorinated pyridines (pentafluoropyridine, 2,6-difluoropyridine, and 2-fluoropyridine) have been studied by using density functional B3LYP method in conjunction with 6-31G(d,p), 6-311G(d,p), 6-31+G(d,p), and 6-311+G(d,p) basis sets. B3LYP geometry optimization and frequency analysis calculations indicate that the pentafluoropyridine cation, 2,6-difluoropyridine cation, and 2-fluoropyridine cation have C 2v, C 2v, and C s structures in the 2A 2, 2A 2, and 2A″ ground states, respectively. The calculated geometries of the cations and the parent molecules were compared. The natural population analysis calculations at the B3LYP level with different basis sets were performed on the three cations and the three parent molecules. The isotropic hyperfine coupling constants in the three cations (radicals) were calculated. The vertical and adiabatic ionization potential (VIP and AIP) values of the pentafluoropyridine, 2,6-difluoropyridine, and 2-fluoropyridine molecules were calculated by using the B3LYP method, and the calculated VIP values are in excellent agreement with experiment.
关键词
氟代吡啶阳离子
密度泛函计算
结构
自然布居分析
电离势
Fluorinated pyridine cations, Density functional calculation, Structure,Natural population analysis, Ionization potential
