Terminal substituent-induced differential aggregation and sensing properties: A case study of neutral benzimidazole-based urea receptors

Abstract

Two neutral benzimidazole-based urea receptors R1 and R2 with varying functional groups led to changes in aggregation as well as chemosensing properties. While R1 displayed aggregation-induced emission (AIE) properties by showing the highest emission in water against binary solvent switching, R2, on the other hand, showed typical aggregation-caused quenching (ACQ) behaviour. Both R1 and R2, however, could sense SO₄²⁻/HSO₄⁻ in an aqueous medium although with different binding affinities, the mechanistic details of which are investigated with the help of different spectroscopic, microscopic, and theoretical approaches.