Synthesis and characterisation of diphenylvinylphosphine-substituted osmium and ruthenium carbonyl clusters; crystal and molecular structures of [Os3(CO)11(Ph2PCHCH2)] and [Os3(µ-H)(CO)9(µ-Ph2PCHCH)]

Abstract

Reaction of the activated clusters [Os₃(CO)_{12 –n}(NCMe)_n](n= 1 or 2) with diphenylvinylphosphine (Ph₂PCHCH₂) afforded [Os₃(CO)_{12 –n}(Ph₂PCHCH₂)_n](n= 1 1 or 2 2) in good yield. Addition of Ph₂PCHCH₂ to [Os₃(µ-H)₂(CO)₁₀] resulted in the formation of [Os₃(µ-H)H(CO)₁₀(Ph₂PCHCH₂)]3. The ruthenium clusters [Ru₃(CO)_{12 –n}(Ph₂PCHCH₂)_n](n= 1 4 or 2 5) have been synthesised by the reaction of [Ru₃(CO)₁₂] with an excess of diphenylvinylphosphine in the presence of a catalytic amount of Na–Ph₂CO. Thermolysis of 1 led to the formation of [Os₃(µ-H)(CO)₉(µ₃-Ph₂PCHCH)]6 in which the vinyl moiety has undergone β elimination. Similarly, 4 and 5 are converted into [Ru₃(µ-H)(CO)₉(µ₃-Ph₂PCHCH)]7 and the known complex [Ru₃(µ-H)(CO)₈(Ph₂PCHCH₂)(µ₃-Ph₂PCHCH)]8 under mild conditions (thermolysis or photolysis). No intermediate species could be detected during the formation of 6–8. All of the new clusters 2–7 have been fully characterised on the basis of their spectroscopic data and the molecular structures of 1 and 6 have been established by single-crystal X-ray analysis.