Electronic Structure of Ligand-Bridged Complexes Containing the [Rh2]3+ Core: ESR Spectroscopy, MO Calculations, and X-ray Structures of the Three Redox Pairs [Rh2(CO)2LL'.mu.-PhNC(Me)NPh2]z [z = 0, 1; L = L' = PPh3, P(OPh)3; L = PPh3, L' = P(OPh)3] | Publicación