Mixed-Metal Cluster Chemistry. Site-Selective Reactions of CpWIr₃(CO)₁₁ with PPh₃ and Bidentate Phosphines: X-ray Crystal Structures of CpWIr₃(µ-dppe)(µ-CO)₃(CO)₆, CpWIr₃(µ-dppm)(µ-CO)₃(CO)₆, and CpWIr₃(µ-dppa)(µ-CO)₃(CO)₆

Abstract

Reactions of CpWIr3(CO)11 (1) with equimolar amounts of phosphines afford the site-selective monophosphine cluster products CpWIr3(µ-CO)3(CO)8−x(L) (L = PPh3 (2a), x = 1; L = µ-dppe (2b), µ-dppm (2c), x = 2) in excellent yields (64–84%). Reaction of 1 with the linear diphosphine dppa, Ph2PC≡CPPh2, affords CpWIr3(µ-dppa)(µ-CO)3(CO)6 (2d) in low yield (15%). From the 31P NMR spectrum and preliminary crystallographic results, PPh3 has been assigned to a radial site in 2a. The structures of 2b, 2c, and 2d have been determined by single crystal X-ray diffraction studies; in these three cases, the bidentate phosphines are diaxially-coordinated. In 2d, the bidentate phosphine is highly strained, with an ∠PC≡C of 147.2(8)°. Crystal data: for 2b, space group = P1̅, a = 18.563(5) Å, b = 11.855(4) Å, c = 10.367(2) Å, a = 67.72(2)°, β = 73.54(2)°, γ = 77.44(2)°, Z = 2, No = 10 230 “observed” reflections (I > 3σ-(I)), R = 0.045; for 2c, space group = P21/c, a = 10.748(12) Å, b = 22.439(5) Å, c = 19.886(14) Å, β = 114.95(8)°, Z = 4, No = 2710, R = 0.087; for 2d, space group = Pmnb, a = 21.608(4) Å, b = 17.843(3) Å, c = 10.134(3) Å, Z = 4,No = 2740, R = 0.032. Show more