A Theoretical Study on the Stability of PtL2 Complexes of Endohedral Fullerenes: The Influence of Encapsulated Ions, Cage Sizes, and Ligands

Abstract

The {η2-(X@Cn)}PtL2 complexes possessing three kinds of encapsulated ions (X = F–, Ø, Li+), three various ligands (L = CO, PPh3, NHCMe), and twelve cage sizes (C60, C70, C72, C74, C76, C78, C80, C84, C86, C90, C96, C100) are theoretically examined by using the density functional theory (M06/LANL2DZ). The present computational results demonstrate that the backward-bonding orbital interactions, rather than the forward-bonding orbital interactions, play a dominant role in the stability of {η2-(X@Cn)}PtL2 complexes. Additionally, our theoretical study shows that the presence of the encapsulated Li+ ion can greatly improve the stability of {η2-(X@Cn)}PtL2 complexes, whereas the existence of the encapsulated F– ion can heavily reduce the stability of {η2-(X@Cn)}PtL2 complexes. Moreover, the theoretical evidence strongly suggests that the backward-bonding orbital interactions as well as the stability increase in the order {η2-(X@Cn)}Pt(CO)2 < {η2-(X@Cn)}Pt(PPh3)2 < {η2-(X@Cn)}Pt(NHCMe)2. As a result, these theoretical observations can provide experimental chemists a promising synthetic direction.