VISIBLE ABSORPTION-SPECTRA OF DIARYL CARBONYL RADICAL-ANIONS

Visible absorption spectra are reported for a series of anion radicals of diaryl carbonyl compounds. The radicals were generated by electrol ytic reduction of benzophenone, p-phenylbenzophenone, and 1-naphthylph enyl and 2-naphthylphenyl ketones as well as di-1-naphthyl and di-2-na phthyl ketones in N,N-dimethylformamide solutions. It has been found t hat the Hammett-Streitwieser equation describes the wave number (upsil on ($) over tilde(max),) of the first intense bands in terms of the po sition constant (sigma(r)(+)) appropriate for the aryl skeleton attach ed in its r position to the carbonyl group. A satisfactory linear corr elation in the form upsilon ($) over tilde(max) = (-1.68 +/- 0.96) x 1 0(3) Sigma sigma(r)(+) (13.48 +/- 0.39) x 10(3) exists for the members of the reaction series. (C) 1997 Academic Press.