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为了考察勒烯衍生物结构与稳定性关系,采用密度泛函理论方法对C80X12(X=H,F,Cl,Br)进行了系统计算究.结表明,在C80X12(X=H,F)异构体中,最低能量异构体都违反五元环分离规则.然而,在C80X12(X=Cl,Br)异构体中,最低能量异构体都满足五元环分离规则.由于van der Waals半径较小,H或F加成到碳笼上时外部原子之间排斥作用小,因此在其优结构中,H或F优先加成到2个五元环共用碳原子上.相反,对于氯化、溴化勒烯,为了避免外部加成原子之间在重空间排斥作用,其优结构中Cl或Br优先加成到1,4-位点上.计算结还显,氢化、卤化反应热(C80+6X2→C80X12)遵循如下顺序,即C80F12>C80Cl12>C80H12>C80Br12.这些结表明勒烯衍生物稳定性和衍生化模与加成原子尺和电性有关.
In order to investigate the relationship between the structure and the stability of the leucene derivatives, the C80X12 (X = H, F, Cl, Br) was systematically calculated using the density functional theory method. However, the lowest energy isomers in C80X12 (X = Cl, Br) all satisfy the five-membered ring separation rule. Since van der Waals Radius of small, H or F addition to the carbon cage on the exclusion of small external atoms, so in its superior structure, H or F preferentially added to two five-membered ring common carbon atoms. On the contrary, for the chlorine In order to avoid the exclusion of external addition atoms in heavy space, Cl or Br is preferentially added to the 1,4-site in the optimized structure. The calculated results show that hydrogenation and halogenation reaction heat (C80 + 6X2 → C80X12) obeys the following order, ie C80F12> C80Cl12> C80H12> C80Br12. These results show that the stability and derivatization modes of the celeryne derivatives are related to the atomic scale and electrical charge.