Reactions of photoexcited C60 with weak organic acids. Novel method for the derivatization of fullerenes

Pyrex-filtered irradiation of C60 solutions in liquid diphenylmethane in the absence of oxygen is shown to result in Ph2CH⋅ radicals, which further react with the electron-deficient C60 to give Ph2CH–C60Hn (n=1, 3, 5). The fullerene ground state to 3C60 transition is suggested to be accompanied by the increase of the fullerene solvation affecting thus the acidity of methylene hydrogens in Ph2CH2 as well as the feasibility of their dissociation. Also, photolysis of C60 solutions in weakly acidic phenylacetylene is shown to lead to the addition of a varying number of phenylethinyl groups to the fullerene core.