We have previously encountered binuclear chromium alkyl hydrides supported β-diketiminate ligand (Nn), which resist reductive eliminate even upon heating.[1] We have established a general route for the synthesis of chromium alkyl hydride complexes (where alkyl = trimethylsilylmethyl, phenyl, benzyl and neopentyl) by hydrogenolysis of Cr(II) alkyls of the type NnCrR(THF). Notably, we find that the chromium neopentyl hydride reacts with benzene, toluene and tetramethylsilane to afford the correspondent alkyl hydride complexes. This is an apparent C-H activation. We are currently studying the reaction mechanism, and our working hypothesis is that the reaction occurs by a dissociation and σ-bond metathesis. The synthesis, structures and exploration of the reactivities of the chromium alkyl hydrides will be discussed. [1] (a) MacAdams, L. A.; Buffone, G. P.; Incarvito, C. D.; Golen, J. A.; Rheingold, A. L.; Theopold, K. H. A stable alkyl hydride of a first row transition metal. Chem. Commun. 2003, 1164-1165, (b) Monillas, W.; Yap, G. P. A.; Theopold, K. A Tale of Two Isomers: A Stable Phenyl Hydride and a High-Spin (S=3) Benzene Complex of Chromium. Angewandte Chemie International Edition 2007, 46, 6692-6694

Curious stability of binuclear alkyl hydrides of chromium and their reaction with hydrocarbons

251st National Meeting (2016)

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