QUANTITATIVE SPECTROSCOPIC STUDIES OF THE PHOTOEXCITED STATE PROPERTIES OF METHANO-[60]FULLERENE AND PYRROLIDINO-[60]FULLERENE DERIVATIVES

UV/vis absorption and fluorescence spectra and fluorescence quantum yi elds and lifetimes of a series of methano- and pyrrolidino-[60]fullere ne derivatives in different solvents are studied systematically. The a bsorption and fluorescence properties of the derivatives with differen t substituents are somewhat different from those of [60]fullerene, but very similar among themselves, indicating that the low-lying transiti ons and the photoexcited state processes are dictated by the electroni c structures of functionalized [60]fullerene cages. The results also a llow an examination of the issue concerning discrepancies between expe rimentally determined transition probabilities and those calculated in terms of the Strickler-Berg equation for fullerene molecules. In addi tion, quenchings of the excited singlet states of the [60]fullerene de rivatives by electron donor N,N-diethylaniline (DEA) and the formation of emissive fullerene-DEA exciplexes in solvents of different polarit ies are investigated.