Towards a Comprehensive Hydride Donor Ability Scale

Authors

  • Dr. Markus Horn,

    1. Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany), Fax: (+49) 89-2180-77717
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  • Dr. Ludwig H. Schappele,

    1. Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany), Fax: (+49) 89-2180-77717
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  • Dr. Gabriele Lang-Wittkowski,

    1. Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany), Fax: (+49) 89-2180-77717
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  • Prof. Dr. Herbert Mayr,

    1. Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany), Fax: (+49) 89-2180-77717
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  • Dr. Armin R. Ofial

    Corresponding author
    1. Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München (Germany), Fax: (+49) 89-2180-77717
    • Department Chemie, Ludwig-Maximilians-Universität 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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