The structures of trimetallic nitride fullerenes M3N@C88: Theoretical evidence of corporation between electron transfer interaction and size effect

DFT calculations demonstrated that the parent cage of both Lu3N@C88 and Gd3N@C88 is D2 symmetrical C88:81 738 and their structures and stability are mainly determined by electron transfer interaction between the encaged cluster and the parent cage. However, for La3N@C88, the parent cage is Cs symmetric C88:81 734, La3N cluster are pyramidal in most screened cages, and the structure and stability of La3N@C88 is determined by both electron transfer interaction and size effect. The calculations can rationalize the recent experimental observations and clearly demonstrate that the size of encaged cluster play a substantial role in determining the structures and stability of M3N@C88.