Synthesis of sulfidoosmium carbonyl cluster compounds by the photochemical decomposition of HOs₃(CO)₁₀(μ-SPh) and its subsequent reactions with selected small molecules. Synthesis and crystal and molecular structure of Os₃(CO)₉(μ₃-CO)(μ₃-S)

Under an atmosphere of carbon monoxide, HOs₃(CO)₁₀(μ-SPh) (I) loses benzene when irradiated to form the new cluster compound Os₃(CO)₉(μ₃-CO)(μ₃-S) (II). II was characterized by a single-crystal X-ray diffraction analysis: space group P1, No. 2, a = 6.912 (2) Å, b = 9.500 (3) Å, c = 13.235 (6) Å, α = 82.63 (3)°, β = 87.43 (3)°, γ = 72.30 (3)°, V = 821.1 (6) ų, Z = 2, ρ_calcd = 3.57 g/cm³. The structure was solved by the heavy-atom method and refined (2258 reflections, F² ≥ 3.0σ(F²)) by full-matrix least-squares to the final residuals R₁ = 0.056 and R₂ = 0.069. The molecular structure of II consists of a triangular cluster of three osmium atoms containing a triply bridging sulfido ligand on one threefold face of the cluster and a triply bridging carbonyl ligand on the opposite threefold face. Each osmium atom contains three linear terminal carbonyl ligands. Two Os-Os separations, 2.826 (1) and 2.825 (1) Å, are slightly shorter than the third, 2.840 (1) Å. In the presence of the reagents H₂, H₂S, COS, and CS₂, I loses both benzene and carbon monoxide when irradiated and yields the products H₂Os₃(CO)₉(μ₃-S) (IV), H₂Os₃(CO)₈(μ₃-S)₂ (V), Os₃(CO)₉(μ₃-S)₂ (VI), and Os₃(CO)₈CS(μ₃-S)₂ (VII), respectively. In the absence of a reagent the hexaosmium disulfido cluster, Os₆(CO)₁₇(μ₄-S)₂ (III), is formed. Compounds III, IV, and V were also obtained by the photodecarbonylation of II in the presence of the appropriate reagent. It is proposed that an unsaturated intermediate such as Os₃(CO)₉(μ₃-S) is traversed in the photoreactions of both I and II. © 1984 American Chemical Society.