Novel Dinuclear (μ-Hydrido)(μ-alkylideneamido)ruthenium Complexes, [(η5-C5Me5)Ru]2(μ-L)(μ-H)(μ-NCHR) (R = Me, Et; L = MeCN, Arene), as Precursors of Active Species for Bimetallic Activation. Dehydrogenative Coupling of Ethylene in a Dinuclear Ruthenium Complex

The dinuclear ruthenium tetrahydride [(η5-C5Me5)Ru(μ-H)2]2 reacts with acetonitrile or propionitrile in the presence of an arene such as toluene or naphthalene to generate the (μ-hydrido)(μ-alkylideneamido)ruthenium complex (Cp‘Ru)2(μ-L)(μ-H)(μ-NCHR) (L = (arene); Cp‘ = η5-C5Me5). The reaction of the (μ-alkylideneamido)ruthenium complex with ethylene gives the bis(ethylene)ruthenium complex [Cp‘Ru(η2-CH2CH2)]2(μ-H)(μ-NCHCH3), which undergoes dehydrogenative coupling of the ethylene ligand to yield the μ-η22-s-cis-butadiene complex (Cp‘Ru)2(μ-η22-CH2CHCHCH2)(μ-H)(μ-NCHCH3).