PHOTOINDUCED ELECTRON TRANSFER BETWEEN FULLERENES (C60/C70) AND ETHYLENEDITHIOTETRATHIAFULVALENE

Electron transfer from ethylenedithiotetrathiafulvalene (EDT-TTF) to photo-excited C 60 /C 70 in polar and in nonpolar solvents has been investigated by laser flash photolysis. The transient absorption band of the triplet state of C60 /C 70 ( 3 C 60 */ 3 C 70 *) was effectively quenched by EDT-TTF with the appearance of the absorption bands of C 60 .- /C 70 .- , showing that the electron transfer takes place from EDT-TTF to 3 C 60 */ 3 C 70 * in polar solvents. Even in non-polar solvents, a small amount of C 61 .- /C 70 .- disappeared by back electron transfer to (EDT - TTF) .+ with second-order kinetics, suggesting the formation of free radical ions. The radical ions disappeared with first-order kinetics in nonpolar solvent, indicating that the radical ions are present as contact ion-pair. In the presence of O 2 , the competition for the quenching of 3 C 60 */ 3 C 70 * takes place between electron transfer from EDT-TTF and energy transfer to O 2 . Protonation reaction of C 60 .- /C 70 .- was also followed in the presence of appropriate proton source.