Comparative Raman study of the Ti complex Cp2Ti(η2-C60) · C6H5CH3 and TixC60 films

Raman spectra from the first Ti fullerene complex Cp 2 Ti(η 2 -C 60 ) · C 6 H 5 CH 3 are presented. Compared to spectra of pure C 60 , the spectra of the Ti complex exhibit a number of new peaks due to the symmetry lowering for C 60 . The A g (2) mode is downshifted by 12 cm −1 compared to C 60 , which corresponds to a charge transfer of one electron per Ti-C 60 bond. This value (6 cm −1 for one transferred electron) is identical to the downshift of the A g (2) mode in alkali metal fullerides with ionic bonding. The spectra of Cp 2 Ti(η 2 -C 60 ) · C 6 H 5 CH 3 were compared to the spectra of evaporated Ti x C 60 films. The A g (2) mode in Ti 4 C 60 showed a downshift of about 25 cm −1 compared to pure C 60 , which corresponds to a charge transfer of one electron per Ti atom; this is similar to the ionic alkali metal fullerides and different from η 2 -C 60 -type bonding.