Heterometallic clusters derived from the unsaturated carbyne-bridged dimolybdenum complexes [Mo2(η5-C5H5)2(μ-CPh) (μ-PCy2) (CO)x] (x = 1, 2)

Abstract

The carbonyl-bridged complex [Mo2Cp2(μ-CPh) (μ-PCy2) (μ-CO)] (1) reacted with [Fe2(CO)9] at room temperature to give the 46-electron trinuclear cluster [FeMo2Cp2(μ3-CPh) (μ-PCy2) (CO)5] (Mo–Mo = 2.6782(4) Å), and a similar Mo2Ru cluster was obtained upon reaction with [Ru3(CO)12] under irradiation with visible-UV light (Cp = η5-C5H5). Compound 1 reacted with [Co2(CO)8] at room temperature to give the 60-electron tetrahedral cluster [Co2Mo2Cp2(μ3-CPh) (μ-PCy2) (CO)7], which in solution exits as an equilibrium mixture of two isomers and presumably displays phosphide and carbyne ligands in a cisoid arrangement. This compound evolved thermally to give a third isomer having these ligands arranged in a transoid way (P–Mo–C = 126.3(1)o, Mo–Mo = 2.9612(6) Å). The dicarbonyl complex [Mo2Cp2(μ-CPh) (μ-PCy2) (CO)2] (2) reacted with W(CO)6 under visible-UV light irradiation to give two thermally unstable isomers of the 46-electron trinuclear cluster [Mo2WCp2(μ3-CPh) (μ-PCy2) (CO)6]. Reaction of 2 with [AuCl(PR3)] (R = Me, p-tol, iPr) in the presence of TlPF6 gave first the corresponding cationic clusters trans-[AuMo2Cp2(μ3-CPh) (μ-PCy2) (CO)2(PR3)]PF6, which then evolved thermally to the more stable isomers cis-[AuMo2Cp2(μ3-CPh) (μ-PCy2) (CO)2(PR3)]PF6 (Mo–Mo = 2.810(1) Å for R = iPr), selectively formed with a syn conformation of the carbyne and Cp ligands, except for the PMe3 complex. In contrast, reaction of 2 with CuCl led to a cluster of composition [CuMo2ClCp2(μ3-CPh) (μ-PCy2) (CO)2], presumably present as a monomer in solution, but certainly appearing in the solid state as a centrosymmetric dimer held by bridging Cu–Cl–Cu interactions (Mo–Mo = 2.8004(5), Cu–Cl = 2.309(1), 2.409(1) Å).