| Abstract: | 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. |
