PHOTOCHROMISM OF QUINOID COMPOUNDS

The paper reviews the studies (mainly performed by the authors) on photochromism of para-quinone derivatives. There are three types of photochromic transformations of quinones. Isomerization of paraquinone structure into ana-quinone one during photochemical migration of aryl, hydrogen or acyl group is common to all these processes. Despite the similarity in structure alterations, the nature of the reactive excited state and the details of photochromic transformation mechanism are quite different in the processes under study. The paper generalizes the data on the influence of chemical structure, medium and temperature on the efficiency of the photochemical and thermal stages of 1-alkyl- and 1-acylanthraquinones photochromic transformations of and analyses the influence of substitutes in an anthraquinone nucleus on the stability of a photoinduced form for 1-aryloxyanthraquinone derivatives.