Synthesis, structural characterisation and nuclear magnetic resonance study of [Ru6C(CO)(15)(mu(3)-eta(1):eta(2):eta(2)-C16H16-mu(2)-O)]: An intermediate in the formation of [Ru6C(CO)(14)(mu(3)-eta(2):eta(2):eta(2)-C16H16)]

The complex [Ru6C(CO)(15)(eta(3)-eta(1):eta(2):eta(2)-C16H16-mu-O)] has been-isolated and fully characterised in solution by H-1 NMR spectroscopy and in the solid state by single-crystal X-ray diffraction analysis. On heating it undergoes quantitative conversion to the carbido cluster. [Ru6C(CO)(14)(mu(3)-eta(2):eta(2):eta(2)-C16H16)], with the expulsion of CO2, and on this basis may be considered as a key intermediate in the formation of the carbido cluster. This complex is a rare example of a molecular system containing both the carbido and oxo ligand, possibly derived from the cleavage of a carbonyl group. which are trapped within a metal-cluster framework. The isolation of this new cluster may be taken to indicate that the initial attack by a co-ordinated carbonyl group appears to take place on the co-ordinated organo moiety, thereby:providing evidence for an intramolecular mechanism.