Electron Transfer from Tetrathiafulvalenes to Photoexcited C70 Studied by Observing Transient Absorption in the Near-IR Region

Article abstract of DOI:10.1246/bcsj.70.1833

The photoinduced electron transfer between C70 and tetrathiafulvalene or bis(ethylenedithio)tetrathiafulvalene in polar and nonpolar solvents and their mixture has been investigated by nanosecond laser photolysis/transient absorption spectroscopy in the visible and near-IR regions.The transient absorption bands of the triplet state of C70 observed in polar solvents decayed upon addition of tetrathiafulvalenes accompanied by the appearance of the transient absorption bands of the radical anion of C70.In benzene, the quenching of the triplet state of C70 was observed without the appearance of the radical anion of C70 within a nanosecond laser pulse, suggesting a collisional quenching of the triplet state of C70 with tetrathiafulvalenes.The quantum yield for the formation of the radical anion via the triplet state of C70 was about 1 for tetrathiafulvalene in benzonitrile.The quantum yield decreased in less polar solvents.The back electron transfer rates were also evaluated in polar solvents.