Hammett-Streitwieser Reaction Constants for the Electroreduction of Diaryl Ketones in Aprotic Media

Abstract

Cyclic voltammetry has been used to measure formal potentials of seven aromatic ketone/ketyl radical anion systems in benzonitrile, acetonitrile , propylene carbonate, acetone, N,N- dimethylformamide, N-methylpyrrolidin-2-one, dimethyl sulfoxide and hexamethylphosphoric triamide. The values measured in each solvent obey the Hammett- Streitwieser equation; the reaction constants were found to depend on the solvent acidity and basicity expressed by acceptor and donor numbers, respectively. The results are discussed in terms of the solvation of the products and reactants of the electrode reaction.