VOLTAMMETRIC STUDIES OF T-BUC60 ANION

Electrochemical studies of the reduction and oxidation of t-BuC60- hav e been conducted at platinum electrodes in tetrahydrofuran and dimethy l sulfoxide. The formal potentials for the first three steps of reduct ion are reported and compared to those of C-60. The fact that these po tentials are displaced in the negative direction from those of C-60 ha s been interpreted in terms of the dominance of electrostatic effects in determining the potentials of fullerenes and their derivatives. Oxi dation of t-BuC60- gives the corresponding radical which takes part in a reversible dimerization reaction. The cyclic voltammetric behavior as a function of scan rate and concentration is consistent with this m echanism and simulations of the data have provided limits on the dimer ization equilibrium and rate constants. Specifically, the equilibrium constant falls in the range of 1.9 to 14 x 10(7) M-1 and the rate cons tant for dimerization is 2 to 40 x 10(8) M-1 s(-1).