New fullerenes of a group IV element: Hf metallofullerenes

Metallofullerenes of the group IV element Hf have been synthesized in a macroscopic quantity for the first time. The species were purified by HPLC and identified to be Hf2C80 and HfC84 by TOF/MS measurement. Their HPLC behavior toward the Buckyprep and 5PBB columns were studied systematically in comparison with those of other known fullerene species and HfC84 is found to have an abnormally large capacity factor for the former column. The UV/VIS/NIR spectrum observed for Hf2C80 and found to include absorption peaks at 406, 511, 567 and 668 nm. No ESR signal could be observed for Hf2C80.