Reactivity of Protons, Tertiary Stannanes, and Alkynes with a Triruthenium Dihydrido Cluster Containing a Face-Capping NHC Ligand

The triruthenium dihydrido cluster compound [Ru3(μ-H)2(μ3-κ2-MeImCH)(CO)9] (1), which contains a basic face-capping N-heterocyclic carbene ligand (MeImCH) derived from the activation of two C−H bonds of 1,3-dimethylimidazol-2-ylidene (Me2Im), reacts (a) with [HOEt2][BF4] to give a cationic trihydrido cluster; (b) with HSnPh3 and HSnBu3 to give tin-containing triruthenium clusters that arise from the Sn−H oxidative addition of two or three molecules of the tertiary stannane and that contain an Me2Im ligand that is formed by coupling of the CH fragment of the MeImCH ligand of 1 with two hydrido ligands; and (c) with various alkynes to give mixtures of many products. A trinuclear cluster that only contains carbonyl groups and an intact face-capping MeImCH ligand has been isolated from the reaction of 1 with dimethyl acetylenedicarboxylate.