The Effect of the Medium Polarity on the Mechanism of the Reaction of Hydroxybenzenes with Hydrazyl Radical in Aprotic Solvents

摘要

Mechanisms of the reaction of di- and trihydroxybenzenes with 2,2 '-diphenyl-1-picrylhydrazyl (stable radical) in aprotic media of different polarity have been elucidated by experimental and quantum-chemical methods. Kinetic, stoichiometric, and activation parameters of the reaction have been determined. In benzene (nonpolar solvent), the studied reaction occurs via the hydrogen atom transfer mechanism; in the polar solvent with weak ionizing ability (i.e. DMSO), the reaction predominantly occurs via the faster mechanism of coupled electron and proton transfer.