Reactivity of the triruthenium ortho-metalated cluster [Ru3(CO)9{μ3-η1,κ1,κ2-PhP(C6H4)CH2PPh}] with tri(2-thienyl)phosphine and tri(2-furyl)phosphine: Formation of 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine complexes via phosphorus–carbon bond forma

Reaction of [Ru3(CO)9{μ3-η1,κ1,κ2-PhP(C6H4)CH2PPh}] (1) with tri(2-thienyl)phosphine (PTh3) in refluxing THF afforded [Ru3(CO)9(PTh3)(μ-dpbm)] (3) {dpbm = PhP(C6H4)(CH2)PPh} and [Ru3(CO)6(μ-CO)2{μ-κ1,η1-PTh2(C4H2S)}{μ3-κ1,κ2-Ph2PCH2PPh}] (5) in 18% and 12% yields, respectively, while a similar reaction with tri(2-furyl)phosphine (PFu3) gave [Ru3(CO)9(PFu3)(μ-dpbm)] (4) and [Ru3(CO)7(μ-η1,η2-C4H3O)(μ-PFu2){μ3-η1,κ1,κ2-PhP(C6H4)CH2PPh}] (6) in 24% and 27% yields, respectively. Compounds 2 and 4 are phosphine adducts of 1 in which the diphosphine ligand is transformed into 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine (dpbm) via phosphorus–carbon bond formation. Cluster 5 results from metalation of a thienyl ring, the cleaved proton being transferred to the diphosphine. Carbon–phosphorus bond cleavage of a PFu3 ligand is observed in 6 to afford a phosphido-bridge and a furyl fragment, the latter bridging in a σ,π-vinyl fashion. The molecular structures of 3, 5 and 6 have been determined by X-ray diffraction studies.