富勒烯和富勒烯衍生物中的Stone-Wales旋转

Stone-Wales旋转是富勒烯异构化的基本方式,了解其特征和规律对于理解富勒烯和富勒烯衍生物的形成至关重要.本文采用密度泛函理论方法系统研究了富勒烯和富勒烯衍生物的Stone-Wales旋转.结果显示,富勒烯异构体趋向于从高B55键(两个五元环共用的边)结构向低B55结构转化,满足独立五元环原则的结构或具有低B55键数的异构体在热力学上更为有利.相反,对于富勒烯衍生物,具有更多B55的异构体不仅在热力学上更有利,而且从动力学角度讲,从满足独立五元环原则的结构向不满足的结构的转变比相反过程更容易.这些结果可以解释目前的相关实验事实,暗示了富勒烯衍生物可能是先衍生化后异构化而形成.

The Stone-Wales rotation in fullerenes and their derivatives

Stone-Wales rotation is a fundamental way to facilitate the isomerism of fullerenes and their derivatives which is of key importance on the formation of fullerenes and their derivatives. A systematic study on the Stone-Wales rotation of fullerenes and their derivatives is performed with density functional theory method. The calculated results demonstrate that the isomers with more pentagon-pentagon fusions （B55 bonds） kinetically tend to transfer into the isomers with fewer B55 bonds, even into IPR-satisfying isomers （if possible）; meanwhile, the isomers satisfying IPR or with fewer B55 are more advantageous in thermodynamics. For fullerene derivatives, however, the isomers satisfying the IPR or with fewer B55 bonds are usually disadvantageous in energetics; moreover, these isomers kinetically tend to transfer into the ones with more B55 bonds. These calculated findings are agreement well with the experimental observations, and more importantly, the calculations reveal that the fullerene derivatives may be formed via addition outward and transferred into other isomers with more B55 bonds via Stone-Wales rotation.