SYSTEMATIC SYNTHESIS OF HEXANUCLEAR PHOSPHIDO-BRIDGED OSMIUM CLUSTERS- CRYSTAL AND MOLECULAR-STRUCTURE OF [OS-6(MU-H)(CO)(22)(MU-PH2)]

The phosphido-bridged cluster [Os-6(mu-H)(CO)(22)(mu-PH2)] and the cor responding phosphinidene-bridged cluster [Os-6(mu-H)(2)(CO)(21)(mu-PH) ] have been prepared from the reaction of [Os-3(CO)(11)(PH3)] with [Os -3(CO)(11)(NCMe)] in toluene. Ina similar reaction, [Os-6(mu-H)(CO)(21 )(NCMe)(mu-PH2)] has been prepared from the reaction of [Os-3(CO)(11)( PH3)] with [Os-3(CO)(10)(NCMe)(2)]. The two Os-6 clusters have been fu lly characterized on the basis of their spectroscopic data and, in the case of [Os-6(mu-H)(CO)(22)(mu-PH2)], by single-crystal X-ray analysi s. In both compounds, two Os-3 triangles are linked by a PH2 group whi ch is terminally bound to each triangle. Thermolysis of [Os-6(mu-H)(CO )(22)(mu-PH2)] and [Os-6(mu-H)(CO)(21)(NCMe)(mu-PH2)] leads to the for mation of [Os-6(mu(6)-P)(CO)(18)](-) and [Os-6(mu-H)(mu-P)(CO)(18)], r espectively.