NEW INTERMEDIATES IN THE REACTION OF BENZOPHENONE PHOTOREDUCTION BY HYDROGEN DONORS

The influence of various factors on the photoreduction of benzophenone by benzhydrol and triethylamine was studied using flash photolysis an d steady state spectroscopic techniques. As a result of the investigat ions conducted, it has been shown that one of the intermediates formed in the reaction is a ketyl radical complex. The second component of t he complex is a hydrogen-donor radical. A benzophenone-triethylamine g round state complex is also produced. This affects the properties of t he detected radical complex. The spectral and kinetic characteristics of the observed intermediates are presented and the mechanism of the p hotoreduction is proposed. The mechanism includes the formation of a l ong-lived exciplex and its decay in two competitive processes: photoch emical reaction of the triplet exciplex leads to a ketyl radical and t hermal reaction of the exciplex leads to a ketyl radical complex.