Preparation and Specific Detection of Zn²⁺ Ions of Polyacylhydrazones with Polymerization‐Induced Emission

Abstract

The trace element Zn2+ plays an important role in the human body, but it is challenging to realize its qualitative and quantitative detection. Herein, inspired by the specific detection of the commercial dithizone to Zn2+, a series of polyacylhydrazones with polymerization‐induced emission (PIE) properties were successfully prepared and applied to the specific recognition and detection of Zn2+. It was found that all selected monomers did not emit fluorescence. In contrast, the as‐prepared polyacylhydrazone could emit strong fluorescence at 455 nm, due to the intramolecular aggregation of acylhydrazone groups along the macromolecular chains, indicating a significant PIE effect. As we expected, the polyacylhydrazone could specifically recognize and detect Zn2+ ions from 17 metal ions by the significantly enhanced fluorescence with a lower limit of detection (LOD) of 66 nM. Additionally, the complexation ratio of 2:1 between the repeating units in polyacylhydrazone and Zn2+, the coordination of Zn2+ with N and O atoms on acylhydrazone groups, and the fluorescence enhancement induced via intramolecular proton transfer were confirmed by 1H NMR and FT‐IR measurements. In conclusion, the successful preparation of PIE‐active polyacylhydrazones and the specific detection of Zn2+ ions provide a useful reference for the molecular design of new functional materials on the base of the traditional detection methods.This article is protected by copyright. All rights reserved