Syntheses, Characterization, and Reactivity of Diruthenium Hydrido Complexes

The reaction of [<i>cis-</i>{(η⁵-C₅H₃)₂(CMe₂)₂}­Ru₂(κ²-4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine)₂­(MeCN)₂]­[OTf]₂, <b>1</b>, with H₂ yields a μ-dihydrido complex, [<i>cis-</i>{(η⁵-C₅H₃)₂(CMe₂)₂}­Ru₂(κ²-4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine)₂­(μ-H)₂]­[OTf]₂, <b>2</b>, in 79% yield. The reaction of <b>2</b> with Et₃SiH affords a mono<i>-</i>μ-hydrido complex, <i>cis-</i>{(η⁵-C₅H₃)₂(CMe₂)₂}­Ru₂(κ²-4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine)₂­(μ-H)]­[OTf], <b>3</b>. The reaction of either <b>2</b> or <b>3</b> (1–2 mol %) with C₆H₆ and Et₃SiH results in the catalytic cleavage of the C–H bond in benzene along with the cleavage of the Si–Et bond to form PhEt₂SiH (23–27% conversion) and C₂H₆. The reaction of <b>2</b> or <b>3</b> (1 mol %) with THF and Et₃SiH results in the cleavage of the C–H bond in THF followed by the insertion of the SiEt₂ group into the C–O bond, forming 2,2-diethyl-1-oxa-2-silacyclohexane (14% conversion) as one of the products