Underlying Mechanisms in Optical Chemosensing of Metals by Imidazoles: A Review

ABSTRACT Chemosensing of metal ions is a matter of great interest for researchers. Imidazole is an electron‐rich molecule that tends to coordinate specifically with metal ions and has an electron‐donor nitrogen atom. Therefore, multiple metals, including Cu 2+ , Mg 2+ , Hg 2+ , Al 3+ , and Zn 2+ , have been reported to employ imidazole‐based chemosensors. This review comprehensively covers metal‐ion detection and relevant governing mechanisms in imidazole‐driven chemosensors. Electron transfer is the most prominent mechanism, while energy transfer, ligand‐to‐metal charge transfer (LMCT), and metal‐to‐ligand charge transfer (MLCT) are the least reported mechanisms describing the interaction between metal ions and imidazoles. These sensors exhibit a trend of lower detection limit for metal ions using fluorescence spectroscopy compared to UV/Vis spectroscopy. Critical analysis highlights some underrepresented metal ions and shows that there is still room for improvement. Furthermore, unraveling the mechanism of interaction between the imidazoles and ions will fascinate researchers to develop economical, sensitive, selective, and robust sensors for deciphering the intricate world of metals.