ON THE PHOTOCHEMICAL DECOMPOSITION OF AROMATIC ALPHA-AZOHYDROPEROXIDES

The photochemistry of some alpha-azohydroperoxides (phenyl(phenylazo)m ethyl hydroperoxide and its halogenated derivatives) was investigated in various solvents by microsecond and nanosecond flash photolysis met hods and steady state product analysis. Photodecomposition of the mole cule, demonstrated by the formation of benzaldehyde, is a major, but n ot the only, photochemical pathway. Investigation of the influence of solvent and substitution on the photoinduced transients provides stron g evidence for alternative photoreactions. One of the species produced by flash photolysis was studied in detail and assigned to a transient zwitterion formed from the alpha-azohydroperoxide by proton transfer via an excited state pathway. Semiempirical calculations add further s upport to the proposed mechanism.