New triosmium–iridium clusters: Synthesis and molecular structure of [Os3Ir2(Cp∗)2(μ-OH)(μ-CO)2(CO)8Cl] (1), [Os3IrCp∗(μ-OH)(CO)10Cl] (2), [Os3IrCp∗(μ-H)(μ-Cl)(η3,μ3-C5H2N(NH2)Br)(CO)9] (3) and [Os3IrCp∗(μ-Cl)2(η2,μ3-C5H3N(NH)Br)(CO)7] (4)

The trinuclear osmium carbonyl cluster, [Os3(CO)10(MeCN)2], is allowed to react with 1 equiv. of [IrCp∗Cl2]2 (Cp∗ = pentamethylcyclopentadiene) in refluxing dichloromethane to give two new osmium–iridium mixed-metal clusters, [Os3Ir2(Cp∗)2(μ-OH)(μ-CO)2(CO)8Cl] (1) and [Os3IrCp∗(μ-OH)(CO)10Cl] (2), in moderate yields. In the presence of a pyridyl ligand, [C5H3N(NH2)Br], however, the products isolated are different. Two osmium–iridium clusters with different coordination modes of the pyridyl ligand are afforded, [Os3IrCp∗(μ-H)(μ-Cl)(η3,μ3-C5H2N(NH2)Br)(CO)9] (3) and [Os3IrCp∗(μ-Cl)2 (η2,μ3-C5H3N(NH)Br)(CO)7] (4). All of the new compounds are characterized by conventional spectroscopic methods, and their structures are determined by single-crystal X-ray diffraction analysis.