2‐Hydroxybenzaldehyde Azine and γ‐Cyclodextrin Based Colorimetric/Fluorescent Probe for Highly Sensitive and Selective Detection of Cu 2

The fluorescent probe provides a simple for detecting Cu 2+ through fluorescence quenching of the Schiff‐base probes by Cu 2+ . However, the azine‐based probes often suffer from poor solubility and dispersibility in water and are easily interfered with by other competing ions, which significantly reduces their applicable potential. In this study, we synthesized a water‐dissoluble and highly fluorescent γ‐Cyclodextrin (γ‐CD)/2‐hydroxybenzaldehyde azine (2‐HBA) inclusion complex for Cu 2+ detection. The inclusion of 2‐HBA into γ‐CD enhances its solubility in water and allows it to emit fluorescence. The as‐synthesized γ‐CD/2‐HBA probe exhibits high sensitivity for colorimetric and fluorescent detection of Cu 2+ , with detection limits reaching 2.72 and 1.53 nM, respectively. The results exceed most of those reported in the literature. The probe's structure and potential mechanism were systematically analysed using the experimental and theoretical methods.