Synthesis, Separation, and Molecular Structures of Endohedral Fullerenes

Endohedral fullerenes represent a novel type of nanostructures, which are characterized by a robust fullerene cage with atoms, ions, or clusters trapped in its hollow. Since the first separation of the endohedral metallofullerene La@C82, a large variety of endohedral structures have been isolated and their endohedral nature has been proved by experimental studies. The world of endohedral fullerenes was significantly enlarged within the past decade by the clusterfullerenes including nitride clusterfullerenes and the new carbon cages including non-IPR (IPR=isolated pentagon rule) structures. With the classification of endohedral fullerenes presented first, we review the synthesis methods of endohedral fullerenes focusing on the new synthetic routes of nitride clusterfullerenes, the extraction and separation of endohedral fullerenes. Finally the intriguing molecular structures of endohedral fullerenes are addressed as well.