The photoreactions of aromatic carbonyl compounds with amines. Part II. The reactions of triplet benzophenone and other ketones with primary and secondary aromatic amines

Abstract

Triplet benzophenone does not react efficiently with aniline, o-toluidine, and diphenylamine to give isolable products. However, flash-photolysis studies showed that the ketone quite efficiently abstracts hydrogen from the amines. From a consideration of the kinetics of decay of the α-hydroxydiphenylmethyl radical, pathways were suggested whereby the radicals may react so as to produce the starting compounds. These results lead to a questioning of the assumption that primary and secondary aromatic amines act purely as physical quenchers for triplet ketones and the conclusion is reached that deactivation may be a result of either or both electron transfer and hydrogen-atom transfer. 9,10-Dihydroacridine reacts with excited benzophenone, benzylideneacetophenone, and benzylideneacetone to give isolable reduction products.