Electron Transfer between Mononuclear Metal Carbonyl Anions (M(CO)₅⁻, M = Mn, Re; CpFe(CO)₂⁻; CpM(CO)₃⁻, M = Cr, Mo) and Trinuclear Clusters (M₃(CO)₁₂, M = Fe, Ru, Os) and between Trinuclear Dianions (M₃(CO)₁₁²⁻, M = Fe, Ru, Os) and Metal Carbonyl Dimers (Mn₂(CO)₁₀ and Cp₂M₂(CO)₆, M = Cr, Mo, W)

Reaction of mononuclear metal carbonyl anions with trinuclear clusters of group 8 (M₃(CO)₁₂, M = Fe, Ru, Os) at ambient conditions leads to four separate outcomes: (1) formation of the metal carbonyl dimer and the trinuclear dianion which occurs whenever the two-electron reduction potential for the dimer is more negative than for the trinuclear cluster, (2) formation of MFe₂(CO)₇⁻ by elimination of Fe(CO)₆ which occurs for M = Re(CO)₆, Mn(CO)_δ, and CpMo(CO)₃, (3) formation of the adduct, MRu₃(CO)₁₁⁻, which occurs for Re(CO)₆, and (4) no reaction when the two-electron reduction potential for the trinuclear complex is more negative than for the dimer. For complexes where the two-electron potential for the cluster is more negative than for the dimer, reaction of M₃′(CO)₁₁²⁻ with M₂ to give M₃′(CO)₁₂ and 2M⁻ is observed. The observed reactions allow an estimate of the two-electron reduction potentials for the trinuclear clusters. The kinetics of all of these reactions indicate a first-order dependence on the oxidant and on the reductant and are most consistent with outer-sphere electron transfer.