Metal-Cage Bonding, Molecular Structures and Vibrational Spectra of Endohedral Fullerenes: Bridging Experiment and Theory

A survey of theoretical and combined experimental/theoretical studies of endohedral metallofullerenes is given with the emphasis on endofullerenes with trimetallic nitride clusters. Three general topics are addressed. First, peculiarities of the metal-cage bonding are discussed. Then, the factors which determine isomerism of carbon cages in endohedral metallofullerenes are reviewed, including formal charge of the fullerene and the carbon cage dimensions in terms of its matching the size and shape of the encapsulated cluster. Finally, the strengths of vibrational spectroscopy as a powerful method in the studies of endohedral fullerenes and importance of theoretical modeling for interpretation of vibrational spectra are emphasized.