REACTION OF PENTAFLUORONITROSOBENZENE WITH [OS3(CO)11(CH3CN)] AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF [OS3(CO)11(MU-ONC6F5)], [OS3(CO)9(MU-3-NC6F5)2], [OS3(CO)11(CH3CN)] AND OS3(CO)12

Reaction of pentafluoronitrosobenzene with [Os3(CO)11(CH3CN)] in THF at room temperature yields a new triosmium cluster, [Os3(CO)11(mu-ONC6F5)] (I), where the pentafluorophenylnitroso ligand has been shown by X-ray crystallography to adopt an unusual bonding mode, with its nitrogen bridging two non-bonded osmium atoms and the oxygen atom bonded to one of the osmium atoms. The separation of [Os3(CO)11(mu-ONC6F5)] (I), [Os3(CO)9(mu3-NC6F5)2] (II) and their parent triosmium clusters, i.e. [OS3(CO)11-(CH3CN)] and OS3(CO)12, by high-performance liquid chromatography is also described.