A. Bartl et al., NEW ELECTRON-SPIN-RESONANCE AND MASS-SPECTROMETRIC STUDIES OF METALLOFULLERENES, Chemical physics letters, 229(1-2), 1994, pp. 115-121
The preparation by are vaporization of graphite rods of metal-containi
ng fullerene samples with metals inside the fullerene molecules is des
cribed. The metals lanthanum, scandium, holmium and yttrium were used
for this study. Results in mass spectrometry confirm the existence and
stability of several Me@C-82 species. ESR spectroscopic measurements
of metallofullerene samples in the solid state and in tetrachloroethan
e solution favour the existence of endohedral systems. The splitting o
f the ESR spectra is interpreted by isotropic hyperfine coupling of an
unpaired electron with the nuclear magnetic moment of a metal ion ins
ide a fullerene molecule. It is concluded that the metal atoms exist i
n ionic form in endohedral fullerenes both in solid and liquid state o
f the fullerene. Furthermore it is shown that there is more than one s
table position of the metal ion inside the fullerene molecule.