Spectroscopic investigations of M(CO)₅-C₆₀ (M = W, MO) complexes: precursors for metal fullerides

Abstract

Photochemical reactions of M(CO)₆ (M = W, Mo) with C₆₀in solution yield η:²-complexes of M(CO)₅ with C₆₀. The complexes have been characterised 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 yielding metal fullerides, which show characteristic reduction in peak width in the variable temperature IR spectra due to orientational ordering. Transitions are manifested in calorimetric studies also. Metal → C₆₀ charge-transfer is observed in IR and XPS. A high temperature IR study of the C₆₀-W(CO)₅ complex reveals sequential elimination of the carbonyls yielding MC₆₀. The study shows that carbonyl complexes can be used as precursors to make transition metal fullerides.