Preparation of Half-Sandwich Stannyl Complexes of Osmium(II)

Trichlorostannyl complexes OsCl(SnCl3)(η6-p-cymene)P (1; P = P(OEt)3 (a), PPh(OEt)2 (b), PPh2OEt (c)) were prepared by allowing the dichloro compounds OsCl2(η6-p-cymene)P to react with an excess of SnCl2, and treatment of complexes 1 with an excess of NaBH4 in ethanol yielded the trihydridostannyl complexes OsCl(SnH3)(η6-p-cymene)P (2). Reaction of trihydridostannyl complexes 2 with alkyl propiolates HCCCOOR led to the trivinylstannyl derivatives OsCl[Sn{C(COOR)CH2}3](η6-p-cymene)P (5, 6; R = Me, Et), which were characterized by spectroscopy (IR and 1H, 31P, 13C, and 119Sn NMR spectra) and by an X-ray crystal structure determination of OsCl[Sn{C(COOMe)CH2}3](η6-p-cymene)[PPh(OEt)2] (5b).