Charge separation, charge recombination and electron transfer reactions in solutions of fullerene-C-60 and phenothiazines

C-60 forms weak charge transfer complexes with phenothiazine and methyl phenothiazine. Charge separation, charge recombination and ion dissociation reactions were investigated in the solution phase following excitation of the charge transfer band of the complexes with picosecond laser pulses. The formation of the triplet state of C-60 on charge recombination, and electron transfer reactions of the singlet and triplet states of C-60 with phenothiazine to give C-60(-.) and cation radicals have been investigated. On longer timescales (> 1 mu s) back electron transfer between C-60(-.) and cation radical takes place. The effect of solvent polarity was studied on the charge recombination and back electron transfer reactions.