Photodecomposition of substituted 4-diethylaminoazobenzenes under visible light irradiation in different solvents

The visible light-induced decomposition of two series of 4-diethylaminoazobenzenes has been studied in solvents of different polarity, in the presence and absence of O-2, in order to clarify the reaction mechanism. Two different paths have been recognised, whose importance depends on the nature of the solvent; both involve the formation of organic free radicals. Decomposition is much faster in acetone than in the other solvents. A strong inhibiting effect of molecular oxygen has been observed in all cases. (C) 2002 Elsevier Science B.V. All rights reserved.