A Highly Selective Detection to Zn2+ by Polyacylhydrazones with Polymerization-Induced Emission

Herein, inspired by the specific detection of the commercial dithizone to Zn2+, a series of polyacylhydrazones with polymerization induced emission (PIE) propertieswere successfully prepared and applied to the specific recognition and detection of Zn2+ . It was found that all selected monomers did not emit fluorescence, while 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+ even in the presence of other 17 metal ions. The lowest detection limit (LOD) of PIE-active polyacylhydrazone to Zn2+ reached 66 nM. In addition, the complexation ratio between the repeating units in polyacylhydrazone and Zn2+ was determined to be 2:1, and the coordination of Zn2+ with N and O atoms on acylhydrazone groups was confirmed by 1H NMR measurements. In conclusion, the successful preparation of PIE-active polyacylhydrazones and specific detection of Zn2+ provide a very instructive guidance for fluorescence detection to other transition metals and molecular design of PIE-active polymers.