Cluster chemistry: XXXVIII. Reactions between M(C2R)(PR′3 (M = Cu,Ag, Au; R = Ph,C6F5; R′ = Me Ph) and H2Os3(CO)10: X-ray structures of Os3Au(μ-CHCHR)(CO)10(PPh3) (R = Ph and C6F5)

The reactions of Os₃(μ-H)₂(CO)₁₀ with a series of Group IB metal acetylide-tertiary phosphine complexes are described. Whereas the compounds M(C₂C₆F₅)(PPh₃) (M = Cu, Ag, Au) afforded the complexes MOs₃(μ-CHCHC₆F₅)(CO)₁₀(PPh₃) cleanly and in high yield, complex mixtures of products were obtained from reactions of the analogous phenylacetylides. The complexes MOs₃(μ-CHCHPh)(CO)₁₀(PPh₃), MOs₃(μ-CHCHPh)(CO)₉(PPh₃)₂ and MOs₃(μ-H)(CO)₁₀(PPh₃) (of known structure), and MOs₃(μ-CHCHPh)(CO)₉(PPh₃)₂ and HMOs₃(CHCPh)(CO)₈ (of unknown structure) were characterised; Au(C₂Ph)(PMe₃) afforded similar derivatives. The reactions proceed by oxidative-addition and hydrogen migration steps; MP bond cleavage reactions also occur to a small extent. The molecular structures of AuOs₃(μ-CHCHC₆R₅)(CO)₁₀(PPh₃) (R = F or H) were determined by X-ray analyses. For R = F, crystals are triclinic, space group P$\text{1}$ with a 9.081(2), b 13.291(2), c 17.419(2) Å, α 84.49(1), β 76.20(2), γ 75.81(2)° and Z = 2; 4622 observed data I > 2.5σ(I)] were refined to R = 0.027, R_W = 0.031. For R = H, crystals are triclinic, space group P$\text{1}$, with a 9.403(4), b 13.448(3), c 13.774(4) Å, α 83.34(2), β 88.66(3), γ 70.21(3)°, and Z = 2; 4405 observed data I > 2.5σ(I)] were refined to R = 0.030, R_W = 0.033. The two molecules differ in the orientation of the Ph rings of the PPh₃ groups, but are otherwise similar to Os₃(μ-H)(μ-CHCHBu^t)(CO)₁₀ with the μ-H ligand replaced by the isolobal μ-Au(PPh₃) group.