A METHODOLOGY FOR THE REVERSIBLE SOLUBILIZATION OF FULLERENES

The poor solubility of certain fullerene derivatives, especially those bearing several fullerene moieties, has hampered the preparation of new materials. We are proposing a strategy which uses fullerenes bearing a readily removable solubilizing group to carry out reaction steps leading to a final product with intrinsic low solubility. This is now possible with the one-step conversion of the t-BOC derivative 8a to C-60 in over 95% yield. This one-pot conversion involves the in situ formation of diene 4 which, after [4 + 2] cycloaddition with dimethyl acetylenedicarboxylate, affords the bicyclic adduct 11 undergoing rapid cycloreversion to C-60 and dimethyl phthalate. This method was tested with two functionalized C-60 derivatives (14 and 18) as a first step toward the preparation of new nanosized molecular allotropes of carbon and rigid fullerene-rich polymers.