A highly selective TPE-based AIE fluorescent probe is developed for the detection of Ag.

The detection of Ag in the environment is very important to determine the level of pollution from silver complexes, which have caused various human health problems. Herein, an aggregation-induced emission (AIE) chromophore (tetraphenylethane, TPE) attached to a benzimidazole group (tetra-benzimidazole, TBI-TPE) is synthesized and utilized to detect Ag in the environment. The strong chelating effect between the benzimidazole group and Ag leads to the formation of aggregates, and strong yellow fluorescence signals were observed after adding Ag into a TBI-TPE solution. The stoichiometry of the complex of TBI-TPE and Ag was established to be 1 : 2 using photochemical and mass spectra measurements. The detection limit of the Ag assay is 90 nM with a linear range from 100 nM to 6 μM. This study provides a facile method to determine Ag in real environmental samples with satisfactory results.