The photochemistry of benz[de]anthracen-7-ones. Part II. Flash photolysis

Abstract

The primary photochemical processes following light absorption by benz[de]anthracen-7-one and some of its 3-, 4-, 6-, and 8-substituted derivatives have been studied by laser ns and conventional µs flash photolysis. The transients observed on laser flash photolysis of benz[de]anthracen-7-one and its 4-anilino-, 6-hydroxy-, and 6-amino-derivatives in benzene are the lowest triplet excited states. The rate constants for triplet quenching by oxygen have been determined. The 6-hydroxy- and 6-amino-benz[de]anthracen-7-ones behave rather like benz[de]anthracen-7-one itself whereas the 8-hydroxy- and 8-amino-derivatives show no transient absorption or dye fading on µs flash photolysis and show only weak transient absorption on laser photolysis. These observations are discussed in relation to the overall light stability of the benz[de]anthracen-7-ones.