Rearrangement of Acetylide and Vinylidene Ligands on the Coordination Spheres of Cluster Complexes. Reaction of the Trinuclear Acetylide Cluster CpWOs₂(CO)₈(C≡CPh) with Mononuclear Metal Hydride Complexes LW(CO)₃H (L = Cp, Cp*)

Reaction of CpWOs₂(CO)₈(C≡CPh) with 1.2 equiv of Me₃NO in a mixture of dichloromethane-acetonitrile at room temperature followed by in situ reaction with hydride complexes LW(CO)₃H, L = Cp and Cp*, in refluxing toluene produced the acetylide cluster complexes CpLW₂Os₂(CO)₉(CCPh)(μ-H) (2a, L = Cp; 2b, L = Cp*) and vinylidene cluster complexes CpLW₂Os₂(CO)₉(CCHPh) (3a, L = Cp; 3b, L = Cp*). Heating of the acetylide or vinylidene complex in refluxing toluene induced a reversible rearrangement, giving a mixture of both isomeric complexes. The structures of complexes 2b and 3b have been determined by single-crystal X-ray diffraction. Crystal data for 2b; space group P2₁/c; a = 34.301 (6), b = 12.319 (4), c = 24.718 (6) Å; β = 103.38 (2)°; Z = 12; final R_F = 0.092, R_w = 0.101 for 8771 reflections with I > 2σ(I). Crystal data for 3b: space group P4₂/n; a = 25.486 (6), c = 9.747 (4) Å; Z = 8; final R_F = 0.034, R_w = 0.030 for 3724 reflections with I > 2σ(I).