Photofragmentation in non-symmetric carbonyl compounds

Abstract

The energy profiles for radical dissociation of the lowest triplet state of some non-symmetric carbonyls have been examined using the MINDO/3 method and employing configuration interaction. The activation barriers in the cleavage process arise from an avoided crossing between two states of different symmetries. Our analysis reveals that the perpendicular motion of carbonyl carbon is an important component in the reaction coordinate. Selectivity of the cleavage of a σ bond adjacent to the chromophore is determined by the third derivative of energy with respect to the reaction coordinate at the starting point of reaction.