Vinylidene, Vinyl, and Carbene Ruthenium Complexes with Chelating Diphosphanes as Ligands

The ruthenium vinylidenes [RuCl2(=C=CHR)(PR′3)2] (1, 2) react with 1,2-C2H4(PCy2)2 (3) to give the chelate complexes [RuCl2(=C=CHR)(κ2-3)] (4, 5) by displacement of the two monodentate phosphane ligands. In contrast, the reaction of the hydrido compound [RuHCl(=C=CH2)(PCy3)2] (6) with excess 3 proceeds by migration of the hydride to the Cα carbon atom of the vinylidene unit and affords the six-coordinate vinyl complex trans-[RuCl(CH=CH2)(κ2-3)2] (7). Protonation of 7, followed by addition of NH4PF6, yields the cationic ruthenium carbene trans-[RuCl(=CHCH3)(κ2-3)2]PF6 (8), together with small quantities of the hydrido compound [RuH(κ2-3)2]PF6 (9). The Grubbs catalyst [RuCl2(=CHPh)(PCy3)2] (10) reacts with both 3 and [Fe(η5-C5H4PPh2)2] (11), also by ligand substitution, to give the corresponding chelate complexes [RuCl2(=CHPh)(κ2-3)] (12) and [RuCl2(=CHPh)(κ2-11)] (13); the latter has been characterized by X-ray crystal structure analysis.