FT-Raman characterization of the antipodal bis-adduct of C60 and anthracene

We studied the mono- and the antipodal bis-adduct of C_(60) and anthracene with FT-Raman spectroscopy. Due to the reduced symmetry, the adducts have a much larger number of Raman-active modes than C_(60) with its icosahedral symmetry. Especially interesting is the fact that in the region of the C_(60) pentagonal pinch mode (PPM) the adducts show two strong peaks, of which the higher one is almost at the same frequency as the C_(60) mode and the lower one is downshifted by 5.4 and 10.5 cm^(-1) for the mono- and bis-adduct, respectively. The higher frequency peak could be explained by a degradation of the adducts into C60. However, calculated Raman spectra of the pure adducts also show two strong peaks in the PPM region, of which the higher frequency one is not PPM related. Finally, the C-H vibrations are the only clear evidence for anthracene in the adduct spectra.