ISSN:
1434-1948
Keywords:
Osmium
;
Carbene complexes
;
Hydrido complexes
;
Diazoalkane complexes
;
Vinyl complexes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The five-coordinate compound [OsHCl(CO)(PiPr3)2] (1) reacts with CH2N2 and other diazoalkanes RCHN2 (R = Ph, CO2Et, SiMe3) in ether or toluene at 25 °C to give instead of the expected insertion products [Os(CH2R)Cl(CO)(PiPr3)2] the isomeric hydrido(carbene)osmium(II) complexes [OsHCl(=CHR)(CO)(PiPr3)2] (2-5) in excellent yields. With Me3SiCHN2 as the substrate, the 1:1 adduct [OsHCl(N2CHSiMe3)(CO)(PiPr3)2] (6) was detected at low temperature as an intermediate. The reactions of 1 with Ph2CN2 and Cl4C5N2 afford the hydrido(diazoalkane)compounds [OsHCl(N2CR2)(CO)(PiPr3)2] (7, 8), which are quite stable and do not eliminate N2 to give the corresponding hydrido(carbene)metal derivatives. Treatment of 3 (R = Ph) with either HCl or HBF4/H2O leads to the cleavage of the Os-H bond and results in the formation of [OsCl2(=CHPh)(CO)(PiPr3)2] (10) and [OsCl(=CHPh)(OH2)(CO)(PiPr3)2]BF4 (11), respectively. The vinyl compound [OsCl(CH=CHPh)(CO)(PiPr3)2] (12) behaves similarly to 1 and affords the carbene complex [OsCl(CH=CHPh)(=CHPh)(CO)(PiPr3)2] (13) upon treatment with PhCHN2. Compound 13 rearranges in solution at room temperature to give the π-allyl complex [Os(η3-PhCHCHCHPh)Cl(CO)(PiPr3)2] (14) as the dominating species. The crystal and molecular structures of 4, 5, 10, and 11 have been determined by X-ray crystallography.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
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