Synthesis and characterisation of diphenylvinylphosphine-substituted osmium and ruthenium carbonyl clusters; crystal and molecular structures of [Os₃(CO)₁₁(Ph₂PCH=CH₂)] and [Os₃(μ-H)(CO)₉(μ-Ph₂PCH=CH)]

Reaction of the activated clusters [Os₃(CO)_12-n(NCMe)_n] (n = 1 or 2) with diphenylvinylphosphine (Ph₂PCH=CH₂) afforded [Os₃(CO)_12-n(Ph₂PCH=CH₂) _n] (n = 1 1 or 2 2) in good yield. Addition of Ph₂PCH=CH₂ to [Os₃(μ-H)₂(CO)₁₀] resulted in the formation of [Os₃(μ-H)H(CO)₁₀(Ph₂PCH=CH₂)] 3. The ruthenium clusters [Ru₃(CO)_12-n(Ph₂PCH=CH₂) _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-Ph₂PCH=CH)] 6 in which the vinyl moiety has undergone β elimination. Similarly, 4 and 5 are converted into [Ru₃(μ-H)(CO)₉(μ₃-Ph₂PCH=CH)] 7 and the known complex [Ru₃(μ-H)(CO)₈(Ph₂PCH=CH ₂)(μ₃-Ph₂PCH=CH)] 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.