Hydride complexes of osmium halides with carbon monoxide, dinitrogen, and tertiary phosphines as co-ligands

Abstract

The complexes [OsH₂Cl₂(PR₃)₃](PR₃= PMePh₂, PEt₂Ph, PEtPh₂, or PPhPrⁿ₂) have been prepared by the amalgamated-zinc reduction, under dihydrogen, of mer-[OsCl₃(PR₃)₃]. The compounds mer-[OsXY(L)(PR₃)₃](X = H or D; Y = Cl or Br; L = CO or N₂; PR₃= PMe₂Ph or PEt₂Ph) result from mer-[OsY₂(L)(PR₃)₃] by sodium borohydride or lithium aluminium deuteride reduction. The ¹H n.m.r. and i.r. spectra of these compounds are recorded and used to assign the configuration of the monohydrido-complexes. The dihydro-complexes react with carbon monoxide, tertiary phosphines and carbon tetrachloride–dichlorine with loss of dihydrogen. With one mole of anhydrous HCl the dihydrido-complexes give the unstable compounds [OsHCl₃(PR₃)₃](PR₃= PMePh₂ or PEt₂Ph) which readily give fac-[OsCl₃(PR₃)₃] and ½H₂ when heated. Dinitrogen does not react with [OsH₂Cl₂(PMePh₂)₃]. The compound mer-[OsHCl(N₂)(PEt₂Ph)₃] reacts with anhydrous HCl in toluene to give [OsCl₂(N₂)(PEt₂Ph)₃] and dihydrogen.