Diphosphine- and CO-Induced Fragmentation of Chloride-bridged Dinuclear Complex and Cp*Ir(μ-Cl)3Re(CO)3 and Attempted Synthesis of Cp*Ir(μ-Cl)3Mn(CO)3: Spectroscopic Data and X-ray Diffraction Structures of the Pentamethylcyclopentadienyl Compounds [Cp*IrCl{(Z)-Ph2PCH = CHPPh2}][Cl]·2CHCl3 and Cp*Ir(CO)Cl2

Abstract

The confacial bioctahedral compound Cp*Ir(μ-Cl)3Re(CO)3 (1) undergoes rapid fragmentation in the presence of the unsaturated diphosphine ligand (Z)-Ph2PCH = CHPPh2 to give the mononuclear compounds [Cp*IrCl{(Z)-Ph2PCH = CHPPh2}][Cl] (2) and fac-ClRe(CO)3[(Z)-Ph2PCH = CHPPh2] (3). 2 has been characterized by 1H and 31P NMR spectroscopy and X-ray diffraction analysis. 2·2CHCl3 crystallizes in the monoclinic space group C2/c, a = 35.023 (8) A, b = 10.189 (2) A, c = 24.003 (6) A, β = 103.340 (3), V = 8,335 (3) A3, Z = 8, and d calc = 1.647 Mg/m3; R = 0.0383, R w = 0.1135 for 8,178 reflections with I > 2σ(I). The Ir(III) center in 2 exhibits a six-coordinate geometry and displays a chelating diphosphine group. Compound 1 reacts with added CO with fragmentation to yield the known compounds Cp*Ir(CO)Cl2 (4) and ClRe(CO)5 (5) in near quantitative yield by IR spectroscopy. Using the protocol established by our groups for the synthesis of 1, we have explored the reaction of [Cp*IrCl2]2 with ClMn(CO)5 as a potential route to Cp*Ir(μ-Cl)3Mn(CO)3; unfortunately, 4 was the only product isolated from this reaction. The solid-state structure of 4 was determined by X-ray diffraction analysis. 4 crystallizes in the triclinic space group P−1, a = 7.4059 (4) A, b = 7.8940 (4) A, c = 11.8488 (7) A, α = 80.020 (1), β = 79.758 (1), γ = 68.631 (1), V = 630.34 (6) A3, Z = 2, and d calc = 2.246 Mg/m3; R = 0.0126, R w = 0.0329 for 2,754 reflections with I > 2σ(I). The expected three-legged piano-stool geometry in 4 has been crystallographically confirmed. The reactivity of the chloride-bridged dimer Cp*Ir(μ-Cl)3Re(CO)3 (1) with the unsaturated diphosphine ligand (Z)-Ph2PCH = CHPPh2 has been examined. Rapid fragmentation of 1 occurs in the presence of excess diphosphine to afford the ionic Ir(III) species [Cp*IrCl{(Z)-Ph2PCH = CHPPh2}][Cl] (2) and fac-ClRe(CO)3[(Z)-Ph2PCH = CHPPh2] (3). 1 reacts rapidly with CO to furnish Cp*Ir(CO)Cl2 (4) and ClRe(CO)5 (5). The attempted synthesis of Cp*Ir(μ-Cl)3Mn(CO)3 from [Cp*IrCl2]2 and ClMn(CO)5 was unsuccessful and afforded compound 4 as the sole isolable product. The solid-state structures of 2·2CHCl3 and 4 have been established by X-ray crystallography.