Identification of processes that occur after reduction and dissolution of C-60 adhered to gold, glassy carbon, and platinum electrodes placed in acetonitrile (electrolyte) solution

Microcrystals of C-60(solid) may be adhered to glassy carbon, gold and plat inum electrodes. When the electrodes containing C-60(solid) are placed in a cetonitrile (0.10 mol L-1 Bu4NClO4) and the potential is scanned or stepped to significantly negative potentials, very fast dissolution processes of t he kind C-60(solid) + ne(-) -->(fast) C-60(n-)(soln) (n = 3-5) occur. In co ntrast, one- and two-electron reductions only leas to a minor level of diss olution of C-60(-) and C-60(2-). Electrochemical quartz-crystal microbalanc e studies on gold electrodes revealed that C-60(2-)(solid) and C-60(-)(soli d) are intermediates in the n greater than or equal to 3 reduction-dissolut ion processes and that a range of adsorption and precipitation steps occur when the dissolved material is oxidized back to C-60(solid). The exact deta ils of the mechanism of the process that occur after reduction of C-60(soli d) to dissolved C-60(n-)(soln) (n = 3-5) under conditions of cyclic voltamm etry depend on the scan rates, electrode material, and switching potentials employed . However, under carefully chosen conditions at a glassy carbon e lectrode, reaction schemes of the kind C-60(solid) + 5e(-) --> C-60(5-)(sol n) and C-60(5-)(soln) reversible arrow(+e-)(-e-) C-60(4-)(soln) reversible arrow(+e-)(-e-) C-60(2-)(w/ad) reversible arrow(+e-)(-e-) C-60(-) (w/ad) ar e operative, where the symbol "w/ad" represents weak adsorption. However st rength of adsorption increases on the order of C-60(-) much greater than C- 60(2-) > C-60(3-) > C-60(4-) > C-60(5-), so that strong adsorption and even solid formation occur under other conditions and only fully surface confin ed C-60(solid) could be detected. The relationship between dissolution, ads orption, and surface attachment processes that accompany the voltammetry of C-60 has been identified.