[Os-3(H)(2)(CO)(10)] derivatives containing the short bite ligands bis(diphenylphosphino) methane and 2-(diphenylphosphino) pyridine

The compounds [Os-3(H)(2)(CO)(10)(dppm)] (1) (dppm=bis(diphenylphosphino)methane) and [Os-3(H)(2)(CO)(10)(Ph(2)PPy)] (2) (Ph(2)PPy=2-(diphenylphosphino)pyridine), in which the dppm and Ph(2)PPy ligands act as monodentate P-bonded, have been obtained by reacting [Os-3(H)(2)(CO)(10)] with dppm or Ph(2)PPy, respectively, in equimolar ratio, in hexane. The dropwise addition of a solution of dppm in hexane to a solution of [Os-3(H)(2)(CO)(10)] in the same solvent, in the molar ratio 1:2, afforded the compound [(H)(2)(CO)(10)OS3(mu-dppm)Os-3(CO)(10)(H)(2)] (3) as a yellow-orange solid. At low temperatures, when the exchange process of the hydrides is hindered, the presence of two isomers, with terminal syn and anti hydrides, was evidenced. The synthesis of compounds 3 was undertaken taking advantage of the long lifetime of the [Os-3(H)(2)(CO)(10)(dppm)] species in solution before its conversion to the corresponding mu-dppm complex. The complex [(eta(6)-C6H6)RuCl2(mu-dppm)Os-3(H)(2)(CO)(10)] (4) was obtained by adding an equimolar amount of the cluster [Os-3(H)(2)(CO)(10)] to a solution of [(eta(6)-C6H6)RuCl2(dppm)] in dichloromethane, The H-1 and P-31 {H-1} NMR spectra, in solution, of the reported compounds are discussed.