A cholesteryl thiazolothiazole derivative for colorimetric sensing of Cu²⁺ and its sol-gel transition

Abstract In the current work, a new thiazolothiazole derivative Chol-TZTZ (1) was synthesized, in which a thiazolothiazole bearing aryl amine groups was linked with four cholesteryl units. Thiazolothiazole derivative 1 displayed a unique colorimetric change from green to blue upon the addition of Cu²⁺via the formation of organic radicals. UV absorption maximum was changed from 395 nm to 700 nm when Cu²⁺ was added. Among the various solvents, cyclohexanone could induce gelation of compound 1. π-π interaction between the thiazolothiazole core and van der Waals forces between the cholesteryl group should be involved in the molecules self-assembly of the gelator chol-TZTZ into fibrous superstructures.