苯乙烯基吡啶类化合物几何结构与光谱的理论研究

采用量子化学密度泛函理论(DFT)方法分别在B3LYP/6-31G*, 6-31G**, 6-31＋G*水平上对苯乙烯基吡啶类化合物进行计算研究. 通过在相同水平下的振动频率分析发现苯乙烯基吡啶类化合物具有C₁对称性, 酯基的碳氧原子与苯环形成不同的离域大π键, 空间位阻和共轭效应使得两苯环处于两个不同平面, 二面角在60°与62°之间. 使用含时密度泛函理论(TD-DFT)方法计算第一激发态的电子垂直跃迁能, 得到最大吸收波长λ_max. 计算结果表明末端烷基链的长度对该类化合物的几何结构与振动光谱、电子光谱无影响.

Theoretical Study on the Structures and Spectra of Stilbazoles

Theoretical studies on stilbazoles have been carried out using density functional theory (DFT) at B3LYP/6-31G*, 6-31G**, 6-31＋G* level to obtain optimized equilibrium structure. The calculation results indicate that the compounds have C₁ structure. The carbon and the oxygens in the ester group come into formation of different large π bonds with the benzene ring and there is a dihedral angle between 60° and 62° because of place blocking and conjugate effects. On this basis, the first vertical excited state electronic transition energy was calculated by time-dependent density function theory (TD-DFT), and λ_max was obtained. The computed results show that the length of alkyl chain in the end of stilbazoles has no effect on the structure and electronic spectra.