Leuco Quinone Dyes

Abstract

The chemistry of quinone dyes has been discussed in a series of books entitled The Chemistry of Synthetic Dyes, edited by Venkataraman. The general chemistry of quinoid compounds has been discussed by Patai. There have been many books that cover quinoid compounds as dyes and pigments but very few discuss the chemistry of the corresponding leuco dyes. Traditional vat dyes are applied to cellulosic fiber in the leuco form. The chemistry of the leuco form of vat dyes is rather simple. Some leuco quinones are quite stable in the solid state and can be stored for a year. Other leuco dyes are unstable in solution and gradually undergo aerial oxidation. In recent years advances in the chemistry of leuco dyes have taken place particularly in the areas of structural identification by means of Hand C-NMR and selective syntheses of aminoquinones, etc. New applications of leuco quinones such as in electro-optical devices and information recording media have enhanced their importance. In these applications, the chemistry of leuco quinones is interesting mainly due to switching from a colored to a colorless system by a redox process.