60]Fullerene–perchlorotriphenylmethide anion triads. Synthesis and study of photoinduced intramolecular electron-transfer processes

Abstract

For the first time an anionic donor, the perchlorotriphenylmethide anion (PTM−), has been covalently bonded to C60, generating the C60–(PTM−)2 triad that is reversibly oxidized to the corresponding C60–perchlorotriphenylmethyl radical triad C60–(PTM˙)2. For the triad C60–(PTM−)2, photoinduced charge-separation can be confirmed to occur via the excited singlet states of the C60 moiety and the PTM anion in polar and nonpolar solvents from quenching of their fluorescence intensities in the region of 700–750 nm and 560–630 nm, respectively. The charge-separation state was confirmed by the nanosecond transient absorption spectra in the visible and near-IR spectral regions. After charge-separation, back electron transfer takes place with a lifetime of about 80 ns. Steady-state concentration of the highly persistent PTM radical was observed after repeated laser light irradiation.