A diphosphine ligand as a bridge between carbide and metal centers in clusters

Article abstract of DOI:10.1021/om00106a029

The reaction of [PPN][Fe₂Co(CO)₉(CCO)] with dmpe (dmpe = 1,2-bis(dimethylphosphino)ethane) generates an ylide-capped cluster, [PPN][Fe₂Co(C)(dmpe)(CO)₈] (1), in which dmpe bridges the carbide ligand and cobalt atom. Protonation of 1 occurs across the Fe-Fe bond to give HFe₂Co(C) (dmpe) (CO)₈ (2), which retains the ylide moiety but has the phosphine bonded to an Fe center on the metal framework instead of the Co atom. Treatment of 1 with Co₂(CO)₈ leads to the isolation of FeCo₂(CO)₉(μ₃-CPMe₂CH ₂CH₂Me₂PFe(CO)₄) (3), in which dmpe bridges between the cluster and a mononuclear species. Clusters 1-3 are all spectroscopically characterized. The molecular structure of 3 has been determined by single-crystal X-ray diffraction. Compound 3 crystallizes in the space group P1 with a = 9.392 (1) A?, b = 10.847 (2) A?, c = 7.946 (1) A?, α = 107.76 (1)°, β = 110.56 (1)°, γ = 88.73 (1)°, V = 718.5 (4) A?3, and Z = 1.