Towards a Comprehensive Hydride Donor Ability Scale |
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Authors: | Dr. Markus Horn Dr. Ludwig H. Schappele Dr. Gabriele Lang‐Wittkowski Prof. Dr. Herbert Mayr Dr. Armin R. Ofial |
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Affiliation: | Department Chemie, Ludwig‐Maximilians‐Universit?t München, Butenandtstrasse 5‐13 (Haus?F), 81377 München (Germany), Fax: (+49)?89‐2180‐77717 |
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Abstract: | Rates of hydride transfer from several hydride donors to benzhydrylium ions have been measured at 20 °C and used for the determination of empirical nucleophilicity parameters N and sN according to the linear free energy relationship log k20 °C=sN(N+E). Comparison of the rate constants of hydride abstraction by tritylium ions with those calculated from the reactivity parameters sN, N, and E showed fair agreement. Therefore, it was possible to convert the large number of literature data on hydride abstraction by tritylium ions into N and sN parameters for the corresponding hydride donors, and construct a reactivity scale for hydride donors covering more than 20 orders of magnitude. |
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Keywords: | carbocations hydride transfer kinetics linear free energy relationships reactivity parameters |
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