摘要
用从头算对丙烯和甲苯2个超共轭体系进行计算,结果表明甲基上氢原子参与超共轭时,其碳氢键键长增大,氢上集居数减少,丙烯、甲苯的甲基旋转势垒为7.61及0.096 kJ/mol.超共轭基作用相当于一带有孤对电子参与共轭之杂原子,超共轭体系不同构型稳定性可用M=sum from i=1 to 3(sinθ_i[sin(θ_i-α)+sinα])来表征。
Two hyperconjugated systems, propene and methylbenzene were studied with ab initio method. The result shows that when a methyl participates in the hyperconjugation, the TC-H is lengthened and the population of H is decreased. The rotation barriers of propene and methylbenzene are 7. 61 and 0. 096 kJ/mol, respectively. The hyperconjugated radical can be considered as a mixed atom with a lone electron pair. The stabilities of these configurations can be characterized by M=
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1991年第10期1353-1356,共4页
Chemical Journal of Chinese Universities
关键词
丙烯
甲苯
超共轭
从头算
Ab mitio, Hyperconjugation, Propene, Methylbenzene, Rotation barrier
