Unusual Ar-H/Rh-H JHH NMR Coupling in Complexes of Rhodium(III): Experimental Evidence and Theoretical Support for an h1-Arene Structure

The synthesis and structural properties of three new hydridorhodium(III) complexes are reported. Hydrogenolysis of the cyclometalated Rh dichloride complexes [RhCl2{(S,S)-benbox(Me2)}] (2a-c; benbox(Me2) = 3,5-dimethyl-2,6-bis[(4-R1-4-R2-4,5-dihydrooxazol-2-yl)methyl]phenyl; R1/R2 = H/Et, H/iPr, Me/Me) gives [RhCl2(H){(S,S)-i.p.-benbox(Me2)H}] (3a-c) in 45% to 85% yield. Compds. 3a-c have unusual features by NMR spectroscopy: in particular, downfield shifted aryl proton resonances (8.88-9.03 ppm) that were coupled to the Rh hydride resonances. Using x-ray crystallog. studies, a variety of solid- and soln.-state characterization techniques, and DFT calcns., these features were attributed to the presence of weak p-type h1-arene interactions in 3a-c. [on SciFinder (R)]

Published in:
Journal of the American Chemical Society, 126, 39, 12492-12502

 Record created 2006-02-27, last modified 2018-03-17

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