Redox behavior of the molybdenum and tungsten metallafullerenes Mo(CO)3(dppe)(η2-C60) (dppe = bis-(1,2-diphenylphosphino)ethane) and W(CO)3(dppb)(η2-C60) (dppb = bis-(1,2-diphenylphosphino)benzene)

Electrochemistry of M(CO)(3)(diphosphine)(eta(2)-C-60) (M = W, diphosphine = 1,2-bis(diphenylphosphino)benzene (1); Mo, diphosphine = 1,2-bis(diphenylphosphino)ethane (2)) shows that they undergo reversibly three fullerene-centred reductions at potential values which are more negative by about 0.2 V with respect to the corresponding steps in free C-60. EPR measurements on the electro-generated monoanions [1](-) and [2](-) seem to support that the unpaired electron, although delocalized on the fullerene moiety, assumes a non-negligible metallic character, thus suggesting that the LUMOs of the two complexes might be significantly contributed to by the metallic fragments. (C) 2000 Elsevier Science S.A. All rights reserved.