“…In 2006, Buck and Maas reported the isolation of the di-and tetra-ruthenium complexes, [Ru2(CO)6(μ-sac)2] and [Ru4(CO)12(μ-sac)4], respectively, from the reactions of Ru3(CO)12 with excess sacH at elevated temperatures [18]. Moreover, these authors found that both sac-containing compounds function as suitable pre-catalysts for the cyclopropanation of nucleophilic alkenes with methyl diazoacetate [18], with the Ru4 system also able to catalyze the intramolecular carbenoid C-H insertion in 2-diazoacetoacetamides to yield βand/or γ-lactams [20,21]. Recently, we reported the first triosmium clusters containing an ancillary sac ligand from the reactions of [Os3(CO)10-n(NCMe)n] (n = 1, 2) with sacH in refluxing benzene.…”