| Abstract: | Photooxidation of Leuco Dyes. XII. Time Resolved Investigations on the Photooxidation of Bis-sulfuric Acid Monoesters of Leucothioindigoid Compounds The photooxidation of 4, 4′-dimethyl-6, 6′-dichlorothioindigosol ( 1 ) was studied by means of laser and conventional flash photolysis. Three transients were detected and assigned to a radical R generated by homolytic splitting of one O S-bond of the parent compound and to two further radicals which are formed from R by hydrolytic cleavage of the second ester group. The latter two radicals are in a protolytic equilibrium with each other and react, depending on the nature of the solvent by H-atom abstraction, or by disproportionation forming the leuco-thioindigoid dye or both dye and leuco dye. A mechanistic scheme is proposed. |
