Bimetallic Cluster Complexes: The Synthesis, Structures, and Bonding of Ruthenium Carbonyl Cluster Complexes Containing Palladium and Platinum with the Bulky Tri-tert-butyl-phosphine Ligand

摘要

The bis-phosphine compounds M(PBu_3~t)~2, M = Pd and Pt, readily eliminate one PBut3 ligand and transfer MPBu_3~t groups to the ruthenium-ruthenium bonds in the compounds Ru_3(CO)_(12), Ru_6(CO)_(17)(μ_6-C), and Ru_6(CO)_(14)(η~6-C_6H_6)(μ_6-C) without displacement of any of the ligands on the ruthenium complexes. The new compounds, Ru_3(CO)_(12)[Pd(PBu_3~t)]_3, 10, and Ru_6(CO)_(17)(μ_6-C)[Pd(PBu_3~t)]_2, 11, Ru_6(CO)_(17)(μ_6-C)[Pt(PBu_3~t)]_n, n = 1 (12), n = 2 (13), and Ru_6(CO)_(14)(η~6-C_6H_6)(μ_6-C)[Pd(PBu_3~t)]_n, n = 1 (15), n = 2 (16), have been prepared and structurally characterized. In most cases the MPBut3 groups bridge a pair of mutually bonded ruthenium atoms, and the associated Ru-Ru bond distance increases in length. Fenske-Hall calculations were performed on 10 and 11 to develop an understanding of the electron deficient metal-metal bonding. 10 undergoes a Jahn-Teller distortion to increase bonding interactions between neighboring Ru(CO)_4 and Pd(PBu_3~t) fragments. 11 has seven molecular orbitals important to cluster bonding in accord with cluster electron-counting rules.