Linkage of two trimetallic clusters through the bridging ligands C3HO2 and C3O2. Crystal structures of three clusters containing the components Os3CHCCO2Os3, Ru3CHCCO2Os3, and Os3CCCO2Os3

Reaction of propynoic acid (CHCCO2H) with [Os3(CO)10(MeCN)2] gives the species [Os3H(CHCCO2)(CO)10] containing a μ-carboxylato ligand and a non-coordinated acetylenic function which may be coordinated further. Reaction of this compound with [M3(CO)10(MeCN)2] (M = Os or RU) gives the linked cluster compounds [Os3(CO)10(CHCCO2)Os3H(CO)10] (1) and [Ru3(CO)10 (CHCCO2)Os3H(CO)10] (2), the crystal structures of which are reported. A comparison of the geometries of the compounds [M3(CO)10(alkyne)] (M = Os or Ru) is possible for the first time; each contains a μ-CO ligand, which is more symmetrical for M = Ru than for M = Os. The coordination geometries of the μ3-alkyne and the overall conformations of the linked clusters are very similar. Decarbonylation of 1 and 2 leads to [Os3H(CO)9(C3O2)Os3H(CO)10] (3) (crystal structure reported) and [Ru3H(CO)9(C3O2)Os3H(CO)10] (4) respectively.