Novel Oxidative Nucleophilic Chemistry Enroute to The Synthesis of C₆₀ Fullerols

Abstract

We have demonstrated a novel cyclosulfation chemistry for the functionalization of C₆₀ Molecules and a new route to the synthesis of fullerol. The cyclosulfation reaction of C₆₀ was performed in neat fuming sulfuric acid at 55–60 °C under N₂. Hydrolysis of these derivatives in the presence of water at 85–90 °C or in aqueous NaOH solution at ambient temperature gave the corresponding polyhydroxylated fullerenes (fullerols) in high yield. Various spectroscopie methods were used to resolve the chemical structure of fullerol. An average of 10 to 12 hydroxyl addends was found in fullerols that can be correlated to the structure of polycyclosulfated fullerene precursors containing 5 to 6 cyclosulfate units. The cyclosulfation chemistry is, presumably, initiated by an one-electron oxidation reaction on C₆₀ Molecules, followed by the attack of nucleophilic anionie sulfate species onto the resulting cationic C₆₀ radical intermediates. Further electron oxidation and intramolecular cyclization of the resulting hydrogen sulfated C₆₀ yielded the desired polycyclosulfated C₆₀ products.