用密度泛函和从头算理论研究3-苯基-2-(4-硒基吗啉基)-5-苯基乙烯基-4H-咪唑啉-4-酮及其衍生物的构型,电子结构和振动光谱

本文测得了四种新型杀菌剂3-苯基-2-(4-硒基吗啉基)-5-苯基乙烯基-4H-咪唑啉-4-酮及其衍生物的FT-Raman光谱,并用密度泛函(DFT-B3LYP)和从头算(ab initio RHF)理论在6-31G(d)的水平上研究了化合物基态的构型,电子结构,并计算了它们的振动光谱。结果显示,HOMO-1轨道的主要来自于Se原子Pz电子的贡献,具有非键轨道特征,而化合物的其它4个最高占有轨道都具有π轨道特征。计算振动波数与实验基频很好的吻合。由于化合物分子结构中存在较大的共轭效应,咪唑啉环内C=N双键的伸缩振动模式明显地向低波数位移50cm-1。

Density Functional and Ab Initio Studies of Geometry, Electronic Structure and Vibrational Spectra of Novel Germicides 4H-Imidazoline-4-One and Its Derivatives

The FT-Raman spectra of 3-phenyl-2-(4'-selenomorpholinyl)-5-phenylvinyl-4H-imidazoline-4-one derivates were recorded and their ground-state geometries,electronic structures and vibrational spectra were studied by DFT-B3LYP and ab initio RHF method with 6-31G(d) basis sets.All five highest occupied molecular orbital(HOMO) orbital have pi-orbital character with the exception of HOMO-1,which has mainly contribution of Pz orbital of Se atom and has non-bond orbital character.The scaled vibrational wavenumber are in good agreement with the observed fundamentals.Because of large conjugation effect,the mode υ(C=N) of 4H-imidazoline-4-one is shifted by about 50cm~(-1) toward lower wavenumber.