Spectroscopic investigations of M(CO)(5)-C-60 (M = W, Mo) complexes: Precursors for metal fullerides

Photochemical reactions of M(CO)(6) (M = W, Mo) with C-60 in solution yield eta(2)-complexes of M(CO)(5) with C-60. The complexes have been characteri sed by IR, UV/VIS, NMR and DSC. They do not show any orientational ordering down to 12 K and all the infrared bandwidths remain the same down to this temperature. The complexes can be decomposed thermally or photochemically y ielding metal fullerides, which show characteristic reduction in peak width in the variable temperature IR spectra due to orientational ordering. Tran sitions are manifested in calorimetric studies also. Metal --> C-60 charge- transfer is observed in IR and XPS. A high temperature IR study of the C-60 -W(CO)(5) complex reveals sequential elimination of the carbonyls yielding MC60 The study shows that carbonyl complexes can be used as precursors to m ake transition metal fullerides.