L-cysteine recognition triggered by Zn2 + complexation with ligand

A new type of benzimidazole-based imine-linked fluorescence chemosensor for Zn2 + was synthesized. Coordination of Zn2 + with the receptor led to enhanced fluorescence while other metals quenched the receptor fluorescence. The resulting complex had a supramolecular assembly with a 1:1 host-guest ratio with variable size. The (1.Zn2 +)n assembly showed high selectivity towards the complexation of L-cysteine even in the presence of other potentially competitive biologically important anionic species.