32159-06-1Relevant academic research and scientific papers
Photooxidation of Arylazo-Naphtholes with Singlet Oxygen
Becker, H. G. O.,Franze, J.
, p. 957 - 964 (2007/10/02)
The reaction of p-substituted 4-arylazo-1-naphtholes 1 and 1-arylazo-2-naphtholes 5 with singlet oxygen (produced by methylene blue-sensitized photolysis) has been studied spectroscopically in methanol as a solvent.The rate constants of dye bleaching are the same, irrespective whether the extinctions of the azo or the hydrazone forms of the tautomeric systems are measured.Both reaction series 1 and 5 afford linear Hammett plots, which is discussed in the light of the azo-hydrazone equilibrium of the dyes and an "ene" mechanism of the reaction with singlet oxygen.It could be shown by short-time spectroscopy that the azo-hydrazone isomerization proceeds much faster than the attack of singlet oxygen on the hydrazone form, which explains all observed facts.
