CN bond orientation in metal carbonitride endofullerenes:A density functional theory study

摘要

The geometric and electronic structures of scandium carbonitride endofullerene Sc3CN@C2n (2n =68,78,80,82,and 84) and Sc(Y)NC@C76 have been systematically investigated to identify the preferred position of internal C and N atoms by density functional theory (DFT) calculations combined with statistical mechanics treatments.The CN bond orientation can generally be inferred from the molecule stability and electronic configuration.It is found that Sc3CN@C2n molecules have the most stable structure with C atom locating at the center of Sc3CN cluster.The CN bond has trivalent form of [CN]3 and connects with adjacent three Sc atoms tightly.However,in Sc(Y)NC@C76 with [NC]-,the N atom always resides in the center of the whole molecule.In addition,the stability of Sc3CN@C2n has been further compared in terms of the organization of the corresponding molecular energy level.The structural differences between Sc3CN@C2n and Sc3NC@C2n are highlighted by their respected infrared spectra.