Structures and Properties of Endohedral Metallofullerene Sc2S@C86

Metallic sulfide fullerenes are compounds with novel structures. Currently, it is an important task to clarify the structures and properties of metallic sulfide fullerenes. A systematic study is performed on Sc2S@C-86 by the density functional theory (DFT) method. The calculated results show that the lowest-energy isomer is IPR-satisfying Sc2S@C-86:63751 (the 9th isomer of C86 in the isolated pentagon rule (IPR)-only sequence), sharing the same cage with Sc2C2@C-86. The second lowest energy isomer is not an isolated-pentagon-rule (non-IPR) Sc2S@C-86:63376. Natural bond orbit (NBO) and theory of atoms in molecules (AIM) analyses show that there are charge transfer and covalent interactions between the encaged cluster and parent cage. The effect of temperature on the concentration is evaluated and the results show that several isomers of Sc2S@C-86 may coexist at the high temperature conditions used for producing metallofullerenes. The IR spectra of the two lowest energy isomers are provided to help experimentally identify the structure of Sc2S@C-86 in the future.