Time-resolved EPR study of fullerene C60 adducts at 240 GHz

The excited triplet states of a series of fullerene C60 mono- and bis-adducts have been studied using high-frequency (240 GHz) TR-EPR spectroscopy. The simulation of the spectra gave the zero-field splitting parameters and the population ratio of the triplet sublevels. Moreover, thanks to the increased spectral resolution available at very high frequencies, the g tensor principal values and principal directions with respect to the ZFS axes were determined. The effect of the number, position and of the nature of the substituents on the triplet parameters is discussed. For some adducts the triplet signal decay was analysed.