Theoretical investigation on the saturated hydrides of F5F7–C60 with in-out isomerism

Abstract

The carbon polyhedrons only composed of pentagons and heptagons (F5F7–Cn) are the analogues of classical fullerenes (F5F6–Cn), but they have been neglected for a long time. Very recently, we have performed a systematical study on classical C60H60 and F5F7–C60H60 without endo C–H bonds and found that the stability of F5F7–C60H60 is comparable to their classical ones. To put further insight into the derivatives of F5F7 polyhedrons, we here performed a systematical density functional theory study on F5F7–C60H60 with 1–10 endo C–H bonds. The calculations demonstrate that some isomers of F5F7–C60H60 are lower in energy than the C60H60 obeying the isolated pentagon rule (IPR) even the parent cages of them are all higher in energy than the IPR one by as much as 350kcal/mol. Meanwhile, the F5F7–C60H60 with six endo C–H bonds is lower in energy than the IPR C60H60 without endo C–H bond by over 300kcal/mol. These results demonstrate that F5F7 polyhedrons should not be neglected at all during the search for the favorable derivatives of carbon polyhedrons and that the repulsion between the added atoms plays an important role in determining the stability of the derivatives of carbon polyhedrons.