ISOLATION AND CHARACTERIZATION OF AN ESR-ACTIVE LA-AT-C-82 ISOMER

A minor isomer of La@C-82 has been isolated with an efficient HPLC method. The isolated minor La@C-82 was well identified as a stable metallofullerene molecule. Both mass-and ESR spectra confirmed that it was La@C-82 with a 0.836-G La-139 hyperfine splitting. Visible and near-IR absorption spectra, cyclic and differential pulse voltammograms, and C-13 hyperfine splitting structures in an ESR spectrum for the sample showed features quite different from those for the major isomer of La@C-82 with a 1.159-G La-139 hyperfine splitting. We concluded that isolated species is a carbon-cage isomer of the major La@C-82.