HAMMETT-STREITWIESER REACTION CONSTANTS FOR THE ELECTROREDUCTION OF DIARYL KETONES IN APROTIC MEDIA

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