[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.