High-yield syntheses of sulphido triruthenium carbonyl cluster complexes containing bis(diphenylphosphino)methane

Abstract

Reaction of thiophenol with [Ru₃(CO)₁₀(µ-dppm)][dppm = bis(diphenylphosphino)methane] in toluene at 85 °C leads to the thiolato hydrido cluster complex [ Ru₃(µ-H)(µ-SPh)(CO)₈(µ-dppm)] in 75% yield. Prolonged heating under the same conditions gives the sulphido complex [ Ru₃(µ₃-S)(CO)₈(µ-dppm)] in 95% yield. This complex reacts with hydrogen to yield the hydrido species [Ru₃(µ-H)₂(µ₃-S)(CO)₇(µ-dppm)]. The above sequence of reactions was repeated with [Ru₃(CO)₈(µ-dppm)₂], leading directly to [Ru₃(µ₃-S)(CO)₆(µ-dppm)₂] in 80% yield. Subsequent formation of [Ru₃(µ-H)₂(µ₃-S)(CO)₅(µ-dppm)₂] is achieved in the presence of hydrogen. These reactions show that co-ordination of thiophenol to dppm-substituted triruthenium clusters inhibits the oxidative cleavage of P–C bonds, while subsequent S–C bond cleavage gives sulphido–triruthenium complexes in high yield. The X-ray structure of the intermediate complex [Ru₃(µ-H)(µ-SPh)(CO)₈(µ-dppm)] has been determined: triclinic, space group P, a= 12.361(l), b= 15.315(2), c= 11.591(2)Å, α= 92.04(l), β= 105.62(l), γ= 112.70(1)°, and Z= 2. The intensities of 5 629 reflections (2 < 2θ < 46°) were measured, giving 4 701 unique reflections with F_o² > 3σ(F_o²). Final R′ and R values were 0.032 and 0.041, respectively. The structure shows that the dppm ligand and the thiolato group span different edges of the cluster with the hydrido ligand bridging the same edge as the thiolato group. The Ru–Ru bond distances are 2.867(1), 2.837(1), and 2.835(1)Å.