C60 and C70 Solvates Studied by Raman Spectroscopy

The formation and phase transformations of C 60 and C 70 solvates with benzene, toluene, and n -hexane have been studied in-solution by Raman spectroscopy for the first time. It was found that C 60 and C 70 solvates exhibit Raman spectra which are quite distinct from pure fullerenes and very similar to spectra from fullerene-sulfur compounds. Two different solvates are found for the C 60 −toluene system in good agreement with recent DSC studies. Upon heating, all three solvates decompose to pure fcc C 60 and all new peaks and shifts of peaks typical for the solvates disappear. No changes on Raman spectra of C 60 and C 70 solvates were found upon cooling to 78 K with the exception of the C 70 −benzene solvate which showed a broad phase transition around 263 K. Some possible explanations for the changes in Raman spectra are discussed.