ENDOHEDRAL RARE-EARTH FULLERENE COMPLEXES

The technique of carbon-arc evaporation has been successfully utilized to encapsulate a wide variety of rare-earth species in carbon cages. We have observed M(m)@C(n) (M = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, or Er) species present in the toluene extracts of the carbon soot using laser desorption mass spectrometry. The presence of multiple-metal species appears to depend strongly on the metal-to-carbon atom ratio found in the starting rods, with the higher metal concentrations favoring multiple-metal incorporation. One often observed dimetallofullerene is M2@C80. Molecular orbital arguments are presented to support a possible icosahedral structure for C80.