Carbonyl Displacement Reaction in Diiron Propane-Dithiolate Complex by Triphenylstibine: Crystal Structure of [Fe2(CO)6-n(SbPh3)n(μ-S2C3H6)] (n = 1 and 2)

Treatment of [Fe2(CO)6(μ-S2C3H6)] (1) with triphenylstibine in a 1:1 molar ratio at room temperature in presence of Me3NO resulted compound [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) in 88% yield as red crystals. When the reaction was carried out under a 1:5 molar ratio in presence of Me3NO, it resulted a monosubstituted compound [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) in 63% yield along with a disubstituted compound [Fe2(CO)4(SbPh3)2(μ-S2C3H6)] (3) in low yield (8%) as red crystals. Reaction of 2 with triphenylstibine in a 1:5 molar ratio under same condition resulted 3 in moderate yield (46%). Compounds 2 and 3 were characterized by elemental analyses, IR, 1H NMR and 13C NMR spectroscopic data. Crystal structures of the compounds were unambiguously determined by single crystal X-Ray diffraction studies. Compound 2 crystalized as monoclinic crystal system with the space group P21/c, a = 9.464(4) A, b = 16.902(7) A, c = 17.081(7) A, β = 101.216(13)° and Z = 4. Compound 3 was triclinic, space group P-1, a = 9.552(3) A, b = 13.985(5) A, c = 16.487(6) A, α = 78.372(16)°, β = 89.976(14)°, γ = 71.638(11)° and Z = 2. Two new diiron propane-1,3-dithiolate complexes, [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) and [Fe2(CO)4(SbPh3)2(μ-S2C3H6)] (3), were synthesized by the displacement of carbonyl groups from [Fe2(CO)6(μ-S2C3H6)] (1) with triphenylstibine, and the resulting complexes were structurally characterized. Solid state molecular structure of compound 2 (left) and compound 3 (right)