Insertion of a phospholide unit into a metal–metal bond: Synthesis and X-ray structure of [Ru3(CO)9(μ:η1:η5-PC4H2Me2)(η1-C6H5)]

The reaction of [Ru3(CO)12] with 3,4-dimethyl-1-phenylphosphole under mild conditions affords three derivatives which were identified by means of spectroscopic methods as the substitution compounds [Ru3(CO)12−x(PhPC4H2Me2)x] (x = 1, 2, 3) in which the phosphole ligand acts as a tertiary phosphine bonded through the phosphorus atom. Thermolysis of the monosubstituted [Ru3(CO)11(PhPC4H2Me2)] in cyclohexane affords two new clusters, characterised as [Ru3(CO)9(μ3:η2:η2:η2-PhPC4H2Me2)] and [Ru3(CO)9(μ:η1:η5-PC4H2Me2)(η1-C6H5)], where the phosphole ring behaves as a six- and seven-electron donor ligand respectively. The reaction with [Os3H2(CO)10] gives the new species [Os3(μ-H)(CO)9(μ3:η1:η1:η2-PhPC4H3Me2)] in which the ligand behaves as a five-electron donor.