Laser flash photolysis study of photophysical and photochemical properties of a higher fullerene, C-76

Photophysical and photochemical properties of C-76 have been investigated by using nano- and picosecond laser flash photolysis methods. In the nanosecond laser flash photolysis of C-76, transient absorption ascribable to the triplet excited state of C-76 (C-T(76)*) was observed in the visible and near-IR regions. From the generation of the absorption band of C-T(76)*, the lifetime of the singlet excited state was estimated to be 1.7 ns. Under the presence of beta-carotene in toluene, C-T(76)* was deactivated by energy transfer to beta-carotene at a 2.6 x 10(9) M-1 s(-1) rate constant. Electron-transfer reaction to C-T(76)* was also confirmed in a benzonitrile solution containing C-76 and tetramethyl-p-phenylenediamine (TMPD) as an electron donor. A bimolecular rate constant for quenching of C-T(76)* by TMPD was estimated to be 7.8 x 10(8) M-1 s(-1).