Reactions of Acetylide Clusters Cp*WRe₂(CO)₉(CCR), R = Ph, C(Me)=CH₂, and Cyclohexenyl, with Thiophenol. Formation of WRe2 Thiolate Alkyne and Vinylalkylidyne Derivatives

Heterometallic acetylide cluster Cp*WRe₂(CO)₉(CCPh) (1a) reacted with thiophenol in refluxing toluene to afford two acetylene clusters Cp*WRe₂(CO)₈(μ₃-SPh)(CH=CPh) (2a) and Cp*WRe₂(CO)₇(μ-SPh)(CH=CPh) (3a). Their structures were determined by X-ray diffraction studies. Crystal data of 2a: space group I2/c; a = 20.017(4) Å, b = 11.869(6) Å, c = 29.622-(5) Å, β = 98.50(2)°, Z = 8, R = 0.039, and R_w = 0.032 for 3279 observed reflections with I > 2 σ(I). Crystal data of 3a: space group P2_1/n; a = 10.839(5) Å, b = 17.112(4) Å, c = 16.581-(7) A, β = 94.16(3)°, Z = 4, R = 0.042, and R_w = 0.042 for 3323 observed reflections with I > 2σ(I). The structure of 2a possesses a V-shaped core geometry with a face-bridging thiolate ligand and a phenylacetylene adopting a μ₃-η² (II) mode, whereas cluster 3a contains a triangular skeleton with an edge-bridging thiolate fragment and a unique μ₃-η²(⊥) phenyl-acetylene ligand. Heating of 2a afforded 3a via elimination of a CO; the latter process could be partially reversed by addition of a CO atmosphere. Upon switching to vinylacetylide clusters Cp*WRe₂(CO)₉ (CCC=CH(CH₂)₄) (1c) and Cp*WRe₂(CO)₉(CCCMe=CH₂) (1d), only the alkylidyne clusters Cp*WRe₂(CO)₇(μ-SPh)₂ (CCH=C(CH₂)₅) (4a) and Cp*WRe₂(CO)₇(μ-SPh)₂(CCH=CMe₂) (4b) were obtained. Crystals of 4a are triclinic, space group P1̅; a = 10.149(1) Å, b = 12.151(4) Å, c = 17.442(2) Å, α = 84.79(2)°, β = 76.40(1)°, γ= 70.39(2)°, Z = 2, R = 0.023, and R_w= 0.022 for 4557 reflections with I > 2 σ(I). Clusters 4, exhibiting an open triangular arrangement, possess two thiolate ligands and an asymmetric vinylalkylidyne weakly bridging a W-Re edge (μ-W—C = 1.858(7) Å, μ-Re—C =2.339(6) Å).