MASS SPECTROSCOPIC AND ESR CHARACTERIZATION OF SOLUBLE YTTRIUM-CONTAINING METALLOFULLERENES YC82 AND Y2C82

Solvent soluble, yttrium-containing fullerenes are extracted from yttrium/carbon soot produced by the carbon-arc fullerene generation method. An yttrium-graphite composite yields solvent extractable molecules such as YC82 and Y2C82 as evidenced by a laser desorption time-of-flight (LD-TOF) mass spectroscopic analysis of the extracts. This is consistent with the very recent results by Smalley et al. where YC82 and Y2C82 are prepared by laser vaporization of yttrium-graphite rods. The present extracts are souble by both toluene and carbon disulfide, but the solubility is much higher in CS2 than toluene. LD-TOF mass spectra also show the presence of a series of peaks due to the dimetallofullerenes Y2C2n (2n = 84; 90 less-than-or-equal-to 2n less-than-or-equal-to 140). The metallofullerenes YC60 and YC70 are not observed in the mildest possible LD conditions under which YC82 and the dimetallofullerenes Y2C82 and Y2C2n are readily observed. ESR spectral results are also reported for the present yttrium-fullerene complexes and indicate the charge separation state of Y3+C82(3-) as has been found for La3+C82(3-) by Johnson et al.