Comportement photochimique de cétones α,β-insaturées sous excitation directe

The initial quantum yields of the primary photochemical processes which occur with five α,β-unsaturated ketones were measured under conditions of monochromatic excitation. The quantum yields of EZ isomerization and possibly of transposition (deconjugation) lead to a quantitative interpretation of the nonradiative deactivation of the S1 (nπ) and S2(ππ) excited states of these ketones. These substances show a remarkable photostability even in the presence of dissolved oxygen. [Journal translation]