Photoinduced electron transfer between C60 and tetrathiafulvalene (TTF) or bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) in polar and non-polar solvents and their mixtures was investigated by nanosecond laser photolysis/transient absorption spectroscopy in the visible and near-IR regions. The transient absorption bands of the C60 triplet (TC*60) observed in polar solvents decay on addition of TTF (or BEDT-TTF), accompanied by the appearance of the transient absorption bands of C.-60. The yields of C.-60 are decreased on addition of O2, revealing that about 10% of C.-60 is produced via the singlet state at donor concentrations of less than 5 × 10-3 M. In benzene, the quenching of TC*60 without the appearance of C.-60 within the nanosecond laser pulse is attributed to collisional quenching. The quantum efficiencies of C.-60 formation via TC*60, which were evaluated from the initial [TC*60] and maximal [C.-60] values, vary with the donor ability and solvent polarity. The forward electron transfer rate constants were evaluated from the decay rates of TC*60 (or the rise rates of C.-60) after multiplying by the quantum efficiencies. The back electron transfer rates are slowed down in polar solvents.
|ジャーナル||Journal of Photochemistry and Photobiology A: Chemistry|
|出版物ステータス||Published - 1997 4|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Physics and Astronomy(all)