Complexes [Os{(E)-CH=CHPh}Cl(=N=CR2)(PiPr3)2] [CF3SO3] [CR2 = CMe2 (1), C(CH2)4CH2 (2)] react with carbon monoxide to give the Δ2-1,2-azaosmetine derivatives [OsCl(=CHCH(Ph)N=CR2)(CO)(PiPr3)2] [CF3SO3] [CR2 = CMe2 (3), C(CH2)4CH2 (4)], as a result of the coordination of carbon monoxide to the osmium atoms of 1 and 2 and the carbon-nitrogen coupling between the styryl and azavinylidene ligands. The structure of 3 in the solid state has been determined by an X-ray diffraction study. Complexes 3 and 4 can be deprotonated with MeLi to give the Δ3-1,2-azaosmetine compounds Os{CH=C(Ph) N=CR2}Cl(CO) (PiPr3)2 [CR2 = CMe2(5), C(CH2)4 CH2 (6)], which react with molecular hydrogen to afford the 2-aza-1,3-butadienes CH2=C(Ph)N=CR2[CR2 =CMe2 (7), C(CH2)4CH2 (8)] and OsH2(η2-H2)(CO)(PiPr3 )2. The carbonylation of the cations of 3 and 4 leads to [Os{(Z)-CH=C(Ph)NH=CR2}Cl(CO)2(PiPr3 )2]+ [CR2 = CMe2 (9), C(CH2)4CH2 (10)]. The [BF4]- salts of 9 and 10 have been obtained by carbonylation of 5 and 6 and subsequent protonation of the resulting η1-azabutadiene intermediates Os{(Z)-CH=C(Ph)N=CR2}Cl(CO)2(Pi Pr3)2 [CR2 = CMe2 (11), C(CH2)4CH2 (12)]. The structure of the [BF4]- salt of 10 in the solid state has also been determined by an X-ray diffraction study.

Financial support from the DGES of Spain (Project PB98-1591) is acknowledged. R.C. thanks the “Ministerio de Ciencia y Tecnología” for a grant.

Peer Reviewed