Reactivity of electron-deficient triosmium quinoline cluster [Os3(CO)9(μ3-η2-C9H6N)(μ-H)] with alkynes

Reactions of the electron-deficient triosmium cluster [Os3(CO)9(μ3-η2-C9H6N)(μ-H)] (1) with various alkynes are described. Cluster 1 readily reacts with the activated alkyne dimethyl acetylenedicarboxylate (dmad) upon mild heating (65–70 °C) to give the adduct [Os3(CO)9(μ-C9H6N)(μ3-MeO2CCCHCO2Me)] (2). In contrast, a similar reaction of 1 with diphenylacetylene affords previously reported compounds [Os3(CO)10(μ-η2-C9H6N)(μ-H)] (3), [Os3(CO)9(μ-C4Ph4)] (4) and [Os3(CO)8{μ3-C(C6H4)C3Ph3}(μ-H)] (5) while with 2-butyne gives only the known compound [Os3(CO)7(μ-C4Me4)(μ3-C2Me2)] (6). The new cluster 2 has been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.