Novel butterfly tungsten-osmium carbido cluster Complexes from the reaction of Os₃(CO)₁₀(NCME)₂ CPW(CO)₃(CH₂SMe)

Condensation of be triosmium acetonitrile complex Os₃(CO)₁₀(NCMe)₂ with the sulfido complex CpW(CO)₃(CH₂SMe) in refluxing THF solution produced three sulfur-containing compounds Os₃(C0)₁₀)(μ-H)(μ-SMe) (1), Os₃(CO)₁₁ [S(Me)CH₂W(CO)₃Cp] (2) and CpWOs₃(CO)₁₂(μ-CH₂)(μ-SMe) (3). Clusters 2 and 3 were products involving a 1:1 combination of starting materials and were characterized by X-ray diffraction studies. Crystals of 2 belongs to monoclinic space group P 2₁/c with a=8.418(2), b = 11.912(2), c = 28.288 Å, β=97.64(2)°, Z=4;R_F=0.044, R_W,=0.044. Crystal dara far 3: space group P 2₁/e, a 18.156(4). b=9.255(6), c = 15.347(4) Å. β = 103.49(2)°, Z = 4;R_F-=0.047, R_W = 0.045. Upon thermolysis in toluene, the methylene cluster 3 released CO and induced C-H bond activation to afford two tetrametallic carbido clusters with formula CPWOS₃(CO)₉(μ₄-C)(μ-H)₂(μ-SMe) (4) and CPWOs₃(CO)₁₁(μ₄-C)(μ-SMe) (5) as the principle products. The first complex possesses a butterfly framework encapsulating a μ₄-C ligmd and a μ-SMe ligand linking a W-Os edge, whereas the second product adopts a puckered, cyclic arrangement of WOs₃ metal atoms with μ-SMe ligand located on a nonbonding Os-Os vector. Complex 4 crystallizes in monoclinic space group P 2₁/c with a=15.633(4) Å, b = 8.699 (3) Å, c=15.422(4) Å, β=93.12(2)=°, Z=4, R=0.036, R_W=0.034 for 2780 observed reflections. Crystal data for 5: space group P nma, a=14.542(3), b=13.710(6), c=11.758(3) Å. Z=4, R_F =0.038, R_W = 0.037 for 1826 observed reflections. A variable temperature¹H NMR study was also presented to demonstrate the solution fluxionality of 5.