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Geometric parameters of transition states of radical abstraction reactions with C...H...C reaction center

Research paper by E. T. Denisov, A. F. Shestakov, T. G. Denisova, N. S. Emel"yanova

Indexed on: 01 Apr '04Published on: 01 Apr '04Published in: Russian Chemical Bulletin



Abstract

An algorithm of calculations of interatomic distances in the transition states (TS) of reactions of hydrogen abstraction by alkyl, allyl, and benzyl radicals from C—H bonds of organic molecules using the enthalpies of the corresponding reactions is proposed. The geometric parameters of the TS of the reactions involving carbon-centered radicals with the C...H...C reaction center, calculated using experimental data, are compared with other characteristics of the reactions and reactants. The r(C...H...C) distance in the TS of the reactions of alkyl radicals with alkanes remains unchanged as the enthalpies of reactions vary, being a characteristic parameter of a given class of reactions. π-Bonds adjacent to the reaction center are responsible for an increase in the parameter r(C...H...C) in the TS.