A deep‐red xanthene‐based highly sensitive fluorescent probe for detection of hypochlorite

Abstract As an oxidant, deodorant and bleaching agent, the hypochlorous acid (HClO) and hypochlorite (ClO − ) are widely used in corrosion inhibitors, textile dyes, pharmaceutical intermediates and in our daily lives. However, excess usage or aberrant accumulation of ClO − leads to tissue damage or some diseases and even cancer. Therefore, it is necessary to develop a fluorescent probe that specifically identifies ClO − . In this article, we synthesized a deep‐red xanthene‐based fluorescent probe (XA‐CN). The strong electron deficient group dicyano endows the probe XA‐CN deep‐red fluorescent emission with high solubility, selectivity and sensitivity for ClO − detection. Studies showed that the probe demonstrated turn‐off fluorescence (643 nm) at the presence of ClO − in dimethylsulfoxide/phosphate‐buffered saline 1:1 (pH 9) solution with a limit of detection of 1.64 μM. Detection mechanism investigation revealed that the electron deficient group ‐CN and the hydroxyl group was oxidized into aldehyde or carbonyl groups at the presence of ClO − , resulting ultraviolet‐visible absorption of the probe blue shifted and turned‐off fluorescence. Furthermore, XA‐CN was successfully used for the detection of ClO − in tap water samples.