Reactions of Ethyne with Some Ruthenium Cluster Complexes Containing dppm

Reactions of ethyne with [Ru₃(μ‐dppm)(CO)₁₀] have given isomeric complexes [Ru₃(μ₃‐C₆H₆)(CO)₆(dppm)], one of which, 2 , contains the dppm chelating an Ru‐atom, together with a hexatrienetriyl ligand attached to the Ru₃ cluster to form a methylideneruthenacyclohexadiene system. The second isomer 3 contains the dppm bridging an Ru−Ru bond, with the C₆H₆ ligand forming a vinylruthenacyclopentadiene system. Also isolated was the open‐chain Ru₃ complex 4 containing a ruthenacyclopentadiene attached to the central Ru‐atom; the other Ru−Ru vector is bridged by a PPh₂CHPPh₂C₄H₅ ligand, formed by a novel insertion of two ethyne molecules into an Ru−P bond. The reaction of ethyne with [Ru₃(μ‐H)(μ₃‐C₂H₂)(CO)₉] proceeded by attack at the coordinated alkyne and at the cluster to give a cluster‐bonded PPh₂CH₂PPh₂CCH system in 7 . Thermolysis of [Ru₃(μ‐H)(μ₃‐C₂SiMe₃)(μ‐dppm)(CO)₇] ( 8 ; refluxing MeOH) in the presence of KF gave [Ru₆(μ‐CCH₂)₂(μ‐dppm)₂(CO)₁₂] ( 9 ; 80%); similar reactions carried out with [RuClCp(PPh₃)₂] also present gave 9 (67%) together with [Ru₃(μ‐H)(μ₃‐C₂H)(μ‐dppm)(CO)₆(PPh₃)] ( 11 ; 23%). The molecular structures of 2 , 3 , 4 , 7 , 9 , and 11 , some as differently solvated forms, have been determined by single‐crystal X‐ray studies.