Novel structures from arc-vaporized carbon and metals: Single-layer carbon nanotubes and metallofullerenes

By covaporizing metals with carbon in a fullerene generator, diverse fullerene-related structures can be produced. Adding cobalt to the graphite anode leads to the production of single-layer carbon nanotubes. We find that the relative abundance of tubes with different diameters can be successfully altered by the presence of various catalyst promoters such as sulfur, bismuth, or lead. If Sc is covaporized in the arc, many Sc-containing metallofullerenes form abundantly. Purified Sc₃@C₈₂ has been obtained by HPLC techniques, and its dynamics have been investigated using electron paramagnetic resonance spectroscopy. The unusually large, strongly temperature-dependent linewidths and the temperature-dependent hyperfine coupling suggest that the Sc atoms form a trimer which rapidly reorients within the C₈₂ cage.