Chelation strategies in spiropyran-based chemosensors for colorimetric and fluorescent sensing of metal ions and anions

Functionalized spiropyran-based chemosensors have attracted global attention due to their capability to undergo reversible conversion from a low-fluorescent spiro form to the highly fluorescent ring-opened merocyanine form in response to various external stimuli. In recent years, there has been extensive research on spiropyran derivatives basically which are modified with functional chelating agents, emerging as robust colorimetric and fluorescent sensors. These functional spiropyran sensors exhibits broad application prospects in the analysis and detection of trace pollutants, and other relevant research fields. Therefore, this review article outlines various chelating agents mainly amine, carboxylic acid and its derivatives, macrocyclic molecules, heterocyclic molecules, organic dyes, copolymers, and nanoparticles appended spiropyrans and demonstrate their utilization as fluorescent and colorimetric sensors in sensing applications as well as coordination behavior toward various metal ions and anions in aqueous and biological systems.