摘要
对十四种取代乙烯 (XX′CCYY′)顺反异构体进行了DFT B3LYP/ 6 31G(d)水平的几何全优化的总能量、总键能的计算 .结果表明 ,对无共轭大π键的二取代乙烯 ,其顺式异构体的总能量比反式异构体的低 ,前沿轨道能隙、总键能和总π键能均比反式异构体的大 ,而对有共轭大π键的体系 ,其情况则刚好相反 .表明对于前者其顺式异构体比反式异构体稳定 。
The fully-optimized molecular geometries and the total energies as well as the total bond energies of cis- and trans-isomers in substituted ethylenes (XX' CCYY') have been calculated using DFT method at B3LYP/6-31G(d) and STO-3G lever. The results show that the. total energy of the cis-isomer is lower than that of the trans-isomer. The frontier orbital energy gap (DeltaE), the total bond energy and the total pi-bond energy of the cis-isomer are lager than those of the trans-isomer for those substituted ethylenes in which there is no pi-electron conjugation. However for the substituted ethylenes with conjugated pi bond, the results are just opposite. Based on the results, it is found that the stability of the cis-isomer is better than that of the trans-isomer for the former, but for the later, it is fully reverse, the order of stability of substituted ethylenes is trans- > cis-, because of the pi-electron conjugation of the trans-isomer molecules is better than that of the cis-isomer molecules.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2002年第3期200-205,共6页
Chinese Journal of Organic Chemistry
基金
湖北省教委基金 (No .99A0 46 )资助项目
