Theoretical Study of Addition Reactions of L4M(M = Rh, Ir) and L2M(M = Pd, Pt) to Li+@C60

The addition reaction of M(Cl)(CO)(PPh 3 ) 2 (M = Rh, Ir) and M(PPh 3 ) 2 (M = Pd, Pt) fragments with X@C 60 (X = 0, Li + ) were characterized by density functional theory (DFT) and the artificial force-induced reaction (AFIR) method. The calculated free energy profiles suggested that the η 2 [6:6]-addition is the most favorable reaction, which is consistent with the experimental observations. In the presence of Li + ion, the reaction is highly exothermic, leading to η 2 [6:6] product of L 4 IrLi + @C 60 . In contrast, an endothermic reaction was observed in the absence of a Li + ion. The encapsulated Li + ion can enhance the thermodynamic stability of the η 2 [6:6] product. The energy decomposition analysis showed that the interaction between metal fragment and X@C 60 fragment is the key for the thermodynamic stability. Among the group IA and IIA metal cations, Be 2+ encapsulation is the best candidate for the development of new fullerene–transition metal complexes, which will be useful for future potential applications such as solar cells, catalysts, and electronic devices.