Photocyclization of diarylethenes: the effect of imidazole on the oxidative photodegradation process

We have studied the photoreaction of 1,2-diarylethenes under aerobic conditions in the presence of various amines to prevent side processes promoted by singlet oxygen. It has been found that the most amines quite effectively deactivate processes associated with singlet oxygen, but primary and secondary amines unlike tertiary ones, react with substrates resulting in various side products. Among the studied amines, the most effective additive for preventing side processes, including those associated with singlet oxygen is imidazole, which is practically not consumed in photoreaction. It was shown that imidazole can also prevents the photodegradation of organic photochromes in solutions. The results obtained can be used in various branches of science, technology and medicine to improve the photostability of photosensitive organics (dyes).