环烯烃双键伸缩振动频率反常现象的密度泛函理论研究  

Density functional theory study of the abnormal C = C bond stretch vibrational frequencies of cycloolefine

作　　者：包佩燕[1] 梁雪 王一波 

机构地区：[1]贵州大学理学院化学系

出　　处：《计算机与应用化学》2005年第5期370-372,共3页Computers and Applied Chemistry

基　　金：贵州省省长基金资助项目;贵州省教育厅人文社会科学项目(2004203)

摘　　要：环烯烃中双键吸收频率的红外光谱实验研究表明从六元环到四元环C=C键的吸收频率向低波数方向移动,但三元环vc=c频率却反常地增加。本文采用量子化学计算中的密度泛函理论,在B3LYP/6-31G基组水平上,对环烯烃CnH2n-2(n=3 -6)的几何结构、振动频率和Laplacian电子密度进行了研究。从电子结构水平的层次,这类化学键的特点分析了出现反常的真正成因结果表明,C=C键的伸缩振动频率出现反常的原因是由于三元环中弯键的存在,使C=C键长缩短所致。IR spectrum studies have been made on cycloolefine systems. The results showed that the number of C = C bond stretch vi-brational frequencies decreased from six-members carbon-ring to four-member carbon-ring but increased in three-members carbon-ring. In this study, Density Functional Theory (DFT) calculations were carried out to investigate the geometries, vibrational frequencies and Laplacian electron density of cycloolefine CnH2n-2(n =3 -6) at the B3LYP/6 -31G* level. The calculated results indicated that the abnormal stretch vibrational frequencies result from the three-members carbon-ring have obvious bent bond, and with the shorter of the carbon-carbon double bond.

关 键 词：环烯烃 振动频率 弯键 Laplacian电子密度 

分 类 号：O641.13[理学—物理化学]