Hydrazone-linked covalent organic frameworks for fluorescence detection of Hg2+

A hydrazone-linked COF (DvDf-C3XJ-COF) with hydrogen-bond reinforcement and abundant coordination sites was synthesized, exhibiting strong fluorescence and high sensitivity/selectivity for Hg²⁺ detection, with a detection limit of 1.65 × 10^-6 M. The fluorescence quenching for Hg²⁺ is attributed to coordination interactions, which occur through a dynamic quenching process.