C36H2异构体的稳定性及其加成位置选择性的研究

使用AM1和PM3两种半经验方法,对所有的C₃₆H₂异构体实行非对称性限制的全优化,并结合频率分析及HF/6-31G单点能计算,确定了各异构体的基态结构及其相对稳定性.在此基础上,通过分析加成位置与异构体稳定性之间的关系,得出三条加成位置选择性的规律.最后,利用π-轨道轴矢量(POAV)方法计算了反应前后碳笼中张力的变化.张力与键级分析的结果表明加成位置选择性的规律不是由碳笼释放的张力决定的,而是由C₃₆H₂体系的总共轭性质决定的.

Studies on the Stability about C36H2 Isomers and Selection Rules for Choosing Positions in Additive Reaction

By using AM1 and PM3 methods, the nonrestrictive symmetrical C 36 H 2 isomers based on symmetrical C 36 ( C 6v , C 6h and D 2d ) fullerenes have been exhaustively searched. According to the relationship between isomer stability and adding positions, we have induced three sorts of laws about H 2 choosing different places in the additive reactions.The results of the POAV analysis show that the reactivity is forced by the intensive strains in the C 36 cages. On the other hand, in order to form stable compounds, the rules which guide H 2 chooses different carbon atoms are mainly determined by the conjugated effects in C 36 H 2 system, rather than strains released in C 36 cages.