Synthesis, light absorption and fluorescence properties of new thiazole analogues of the xanthene dyes

Abstract

The synthesis of a new class of cationic dye is described, whose chromophoric system is formally related to that of the cationic xanthene dyes in which one of the aminophenyl rings is replaced by a 2-aminothiazole ring. The light absorption and fluorescence properties of a range of representative dyes of this type have been investigated. The dyes were found to absorb at shorter wavelengths than their xanthene analogues ( λ max 490–506 nm in methanol), in agreement with theoretical predictions, and they also showed moderate to intense fluorescence in dichloromethane solution, with Stokes shifts ranging from 33 to 50 nm.