Imidazole- and phenyl ring-containing luminescent materials for highly sensitive Fe3+ detection and acid–base stimulation anti-counterfeiting encryption applications

Abstract

The design and synthesis of organic, blue-luminescent materials containing imidazole and benzene rings to stimulate desirable properties is described. With the synthesis of triphenylamine and phenanthrenequinone as the core, benzene and 1-phenylimidazole substituents on the N-1 position were changed. The compound exhibits dark blue luminescence. Imidazole can be protonated under acid–base stimulation to realize ON–OFF–ON fluorescence conversion and a change in fluorescence colour, representing a reversible and controllable fluorescent switch. The designed 4-(1H-phenanthro[9,10-d]imidazol-2-yl)-N,N-diphenylamine (4MZ-PT) exhibits deep-blue luminescence and high stability, with moderate hybridized local and charge-transfer transition intensity. The recognition effect of Fe³⁺ in high and medium concentrations is good, and a 42-fold quenching of fluorescence with tetrahydrofuran solution as a solvent was observed.