Synthesis and Reactivity of Ruthenium Amine and Amido Complexes.

Abstract

Late transition metal complexes with non-dative and π-donating ligands are important substrates in a variety of synthetic transformations including C-N or C-O bond forming processes and C-H bond activation reactions. Examples of such complexes are few relative to early and middle transition elements in high oxidation states, and the understanding of the chemistry of such systems with amido, oxide, imido, or oxo ligands has lagged compared to related M-C or M-H linkages. A series of Ru(II) amido complexes of the type TpRu(L)(L')NHR (L = L' = PMe3 or P(OMe)3 or L = CO and L' = PPh3; R = H, Ph, or tBu) were prepared and characterized. These complexes exhibit basic reactivity and will deprotonate C-H bonds as evidenced by the reactivity with weak acids such as 1,4-cyclohexadiene or phenylacetylene. The nucleophilicity of the complexes was also examined by reaction with ethylbromide. In addition, oxidation of the phenyl amido complexes with AgOTf, Cp2FePF6, or I2 resulted in 4,4' carbon-carbon coupling of the aryl group of the anilido ligands to produce the bimetallic complexes [TpRu(L)(L')NHC6H4-]2[X]2 (X = OTf -, PF6-, or I-). The five-coordinate amido complexes (PCP)Ru(CO)NHR (PCP = C6H3(CH2PtBu2)2; R = H or Ph) were synthesized and characterized. The parent amido complex was prepared by deprotonation of (PCP)Ru(CO)(NH3)Cl and the phenyl amido