Selective reduction and extraction of Gd@C82 and Gd2@C80 from soot and the chemical reaction of their anions

Gd@C82 and Gd2@C80 were selectively reduced and extracted from the raw soot in a high yield by using Al-Ni alloy in toluene/tetrahydrofuran (THF). By tuning the ratio of toluene and THF, Gd2@C80 with purity higher than 95% was isolated directly from the raw soot without high performance liquid chromatography (HPLC) purification. Furthermore, we found that the anions of Gd@C82 and Gd2@C80 could react with aqueous NaOH to form water-soluble Gd-metallofullerols, which are potential magnetic resonance imaging contrast agents.