OSMIUM NITROSYL COMPLEXES WITH OSMIUM-TIN BONDS - CRYSTAL-STRUCTURE OF OS[SN(P-TOLYL)(3)](NO)(CO)(2)(PPH3)

Oxidative addition of the tin-hydride bond of (p-tolyl)(3)SnH to the f ormal osmium(0) nitrosyl complexes, OsCl(NO)(PPh3)(3) and ''OsH(NO)(PP h3)(2)'', affords the osmium(II) stannyl complexes, Os[Sn(p-tolyl)(3)] HCl(NO)(PPh3)(2) (1), and Os[Sn(p-tolyl)(3)]H-2(NO)(PPh3)(2) (2) respe ctively. ''OsH(NO)(PPh3)(2)'' was generated in situ by thermal elimina tion of H-2 from OsH3(NO)(PPh3)(2) (5). It was established from H-1 an d P-31 NMR evidence that 1 has two cis phosphine ligands, one of which is trans to the hydride ligand and the other trans to the stannyl lig and. The high trans influence of the hydride Ligands confers lability on one phosphine ligand, which can be readily replaced by reaction wit h sodium dimethyldithiocarbamate forming OsH[Sn(p-tolyl)(3)](S2CNMe2)( NO)(PPh3) (3), and reaction with carbon monoxide gives eventually, aft er displacement of one triphenylphosphine and loss of HCl, Os[Sn(p-tol yl)(3)](NO)(CO)(2)(PPh3) (4), a formal osmium(0) stannyl complex. The crystal structure of this five-coordinate osmium-tin complex, 4, has b een determined. (C) 1997 Elsevier Science S.A.