Electron Paramagnetic Resonance of Modified Fullerenes

EPR spectroscopy of modified fullerenes is considered. In particular are described fullerene derivatives in the first excited triplet state, radical species produced by photoexcitation and the peculiar shape of their EPR spectra, and high spin species and processes involving the interaction of photoexcited fullerenes with free radicals. A brief introduction is included on EPR spectroscopy of excited state molecules and on time resolved EPR techniques, used for studying them. A section deals with the spectra of triplet excited mono- and poly-adducts of C₆₀, and a section is devoted to the peculiar spin polarisation characteristics of the spectra of radical pairs produced by photo electron transfer from an electron donor to fullerene. Spin polarisation effects, which are always present in the spectra of photoexcited systems, are described in relation to the process of generation of the excited triplet, and in the interaction of excited triplets with free radicals. One of the last sections deals with the EPR spectra of fullerenes covalently linked to one or two stable free radicals and in particular with the effect of pulsed light irradiation on their spectra.