Iridium-carbonyl clusters: VI. Mixed-metal clusters via metal-hydride coupling. Synthesis of CpMM′ 3(CO) 11 (M = Mo, W; M′ = Co, Ir) and the crystal structure of CpMoIr 3(CO) 11

Abstract

The reaction of CpM(CO) 3H (M = Mo, W), with IrCl(CO) 2( p-toluidine) leads to the species CpMIr 3(CO) 11; reaction of CpM(CO) 3H with Co 4(CO) 12 produces the known species CpMCo(CO) 11 in high yield. The newly-reported species CpMoIr 3(CO) 11 has been subjected to an X-ray structural analysis. It crystallizes in the centrosymmetric orthorhombic space group Pbca (No. 61) with a 12.2830(15), b 13.5113(18), c 24.9418(30) Å, V 4139.3(9) Å 3 and Z = 8.Diffraction data were collected with a Syntex P2 1 automated diffractometer (Mo- K α radiation, 2θ 4.0–45.0°) and the structure was refined to R 5.4% for all 2421 data ( R 4.5% for those 2141 data above 3σ(¦ F 0¦)). CpMoIr 3(CO) 11 is neither isomorphous nor isostructural with the known species CpWIr 3(CO) 11 or CpMoCo 3(CO) 11. It differs by possessing three bridging carbonyl ligands which encircle one MoIr 2 face of the tetrahedral MoIr 3 cluster. The structure is completed by a Cp ligand on Mo and eight terminal carbonyl ligands (one on the molybdenum atom, three on the unique iridium atom and two each on the iridium atoms associated with the MoIr 2(μ-CO) 3 moiety). The molecule has approximate C s symmetry.