Fluxional behaviour of phosphole and phosphine ligands on triosmium clusters

The unsaturated cluster [Os3(μ-H)2(CO)10] reacts with a variety of π-conjugated phosphole ligands to give mono-substituted derivatives with fluxional behavior, while the reaction of [Os3(CO)10(CH3CN)2] with cyanoethyldiphenylphosphine affords mono- and bis(phosphine)-substituted clusters, whose dynamic behavior is studied by variable-temperature 1H and 31P NMR spectroscopy.