Syntheses, Characterization, and Reactivity of Diruthenium Hydrido Complexes

The
reaction of [cis-{(η5-C5H3)2(CMe2)2}­Ru2(κ2-4,4′-di-tert-butyl-2,2′-bipyridine)2­(MeCN)2]­[OTf]2, 1, with H2 yields a μ-dihydrido complex, [cis-{(η5-C5H3)2(CMe2)2}­Ru2(κ2-4,4′-di-tert-butyl-2,2′-bipyridine)2­(μ-H)2]­[OTf]2, 2, in 79% yield. The reaction of 2 with Et3SiH affords a mono-μ-hydrido complex, cis-{(η5-C5H3)2(CMe2)2}­Ru2(κ2-4,4′-di-tert-butyl-2,2′-bipyridine)2­(μ-H)]­[OTf], 3. The reaction of either 2 or 3 (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 2 or 3 (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.