| Abstrakt: |
The dichlorodihydridoruthenium(IV) compound [RuH2Cl2(PiPr3)2] (4) was prepared from [RuCl2(C8H12)]n (3), PiPr3, and H2 in 2-butanol via the chlorohydridoruthenium(II) derivative [RuHCl(H2)(PiPr3)2] (5) as an intermediate. The synthesis of 5 was achieved under similar conditions from 3, PiPr3, H2, and 2-butanol in the presence of NEt3. Compound 4, which was characterized by X-ray crystal structure analysis, reacts with excess phenylacetylene to give the phenylvinylidene complex [RuCl2(=C=CHPh)(PiPr3)2] (7) and with propargylic alcohols or derivatives thereof to afford the vinylcarbene complexes [RuCl2(=CHCH=CR2)(PiPr3)2] (9, 10), respectively. From 5 and terminal alkynes RC≡CH the chlorohydridovinylidene compounds [RuHCl(=C=CHR)(PiPr3)2] (11, 12) were obtained. The phenylvinylidene complex [RuCl2(=C=CHPh)(PCy3)2] (15) was prepared from phenylacetylene and either [RuH2Cl2(PCy3)2] (14) or one of the carbene deriva-tives [RuCl2(=CHR)(PCy3)2] (16, 17) as starting materials. The X-ray crystal structure analysis of 15 confirms a distorted square-pyramidal geometry with the vinylidene ligand in the apical position. The interconversion of 4 to 5 and of the tricyclohexylphosphane counterparts 14 to 13 was achieved by hydrogen transfer from 2-propanol in the presence of PR3. The reverse reaction occurs upon treatment of 5 or 13 with the corresponding phosphonium salt [HPR3]Cl or HCl, respectively. |
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