Date: September 15, 2006
Creator: Feng, Yuee; Gunnoe, T. Brent; Grimes, Thomas V. & Cundari, Thomas R., 1964-
Description: This article discusses octahedral [TpRu(PMe3)2OR]n+ Complexes (Tp = hydridotris(pyrazolyl)borate. Abstract: The Ru(II) complexes TpRu(PMe3)2OR (R = H or Ph) react with excess phenylacetylene at elevated temperatures to produce the phenylacetylide complex TpRu(PMe3)2(C≡CPh). Kinetic studies indicate that the reaction of TpRu(PMe3)2OH and phenylacetylene likely proceeds through a pathway that involves TpRu(PMe3)2OTf as a catalyst. The reaction of TpRu(PMe3)2OH with 1,4-cyclohexadiene at elevated temperature forms benzene and TpRu(PMe3)2H, while TpRu(PMe3)2OPh does not react with 1,4-cyclohexadiene even after 20 days at 80 ˚C. The paramagnetic Ru(III) complex [TpRu(PMe3)2OH][OTf] is formed upon single-electron oxidation of TpRu(PMe3)2OH with AgOTf. Reactivity studies suggest that [TpRu(PMe3)2OH][OTf] initiates reactions, including hydrogen atom abstraction, with C-H bonds that have bond dissociation energy < 80 kcal/mol. Experimentally, the O-H bond strength of the Ru(II) cation [TpRu(PMe3)2(OH2)][OTf] is estimated to be between 82 and 85 kcal/mol, while computational studies yield a BDE of 84 kcal/mol, which are in reasonable agreement with the observed reactivity of [TpRu(PMe3)2OH]+.
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