A highly selective supramolecular fluorescent probe for detection of Au3+ based on supramolecular complex of pillar[5]arene with 3, 3′-dihydroxybenzidine

This study describes a highly sensitive and selective fluorescence sensor for detection of Au3+ ions. It uses a 3, 3-dihydroxybenzidine/phosphate pillar[5]arene inclusion complex (DHB/PP5A IC) in a pure water phase. The host-guest IC of DHB and PP5A was prepared using the saturated solution method, which greatly improved the water solubility of DHB. The inclusion behavior and stoichiometric ratio of DHB and PP5A were investigated using the spectroscopic titration method. The IC was further characterized by 1H NMR, 2D NOESY, SEM, FT-IR, and XRD methods. The theoretical calculation identified the most stable inclusion mode of the DHB/PP5A IC. Fluorescence spectroscopy studies showed that the DHB/PP5A IC has a rapid, highly sensitive, and selective fluorescence quenching effect on Au3+ ions in pure water, with a detection limit of 6.9 × 10−8 M. The IC has the advantages of strong interference resistance and good adaptability across a wide range of pH values. The IC reported in this study provides a new approach to the detection of Au3+ ions in the fields of environmental and biomedical analysis.