Ligand substitution in HC(O)CCo3(CO)9 with 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd): Diphosphine ligand fluxionality, decarbonylation of the formyl moiety and competitive P-Ph bond cleavage reactivity

The formyl-substituted cluster HC(O)CCo3(CO)9 reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) to give HC(O)CCo3(CO)7(bpcd) (2). Thermolysis of HC(O)CCo3(CO)7(bpcd) leads to decarbonylation of the formyl moiety and formation of the methylidyne-capped cluster HCCo3(CO)7(bpcd) (4) and concurrent production of the phosphido-bridged cluster Co3(CO)7[μ2,η2,η1-P(Ph)CC(PPh2)C(O)CH2C(O)] (5). The three bpcd-derived clusters 2, 4, and 5 have been fully characterized in solution and their molecular structures established by X-ray crystallography.