Hydroxypyridinone based chelators: a molecular tool for fluorescence sensing and sensitization

Among the currently developed analytical tools, sensors based on fluorescence detection have received immense recognition owing to their high sensitivity, low cost, fast response, and simplicity. The design and synthesis of fluorescence chemosensors to sense metals that are of environmental and biological relevance are of appreciable interest. The efficacy of fluorescent sensors relies on two crucial features: a metal binding unit and a fluorophore that can absorb and emit light. The electronic structure of the sensor is altered upon complexation, leading to a change in light emission or absorption intensity and wavelength. Hydroxypyridinones, a class of N-heterocyclic metal chelators, are appreciated as magnificent chemical tools in metal chelation with a higher affinity towards hard metals, displaying various medical, biological, and industrial applications. However, such compounds are scarcely used as sensors. This article outlines the recent invention of fluorescence chemosensors related to hydroxypyridinone based chelators for the selective sensing of analytes of biological and environmental importance. This discussion involves the structural parameters, coordination mode, and other approaches that helped develop highly selective fluorescence sensors for the ions. In addition, the luminescence properties of the hydroxypyridinones in the energy transfer process of lanthanide chelates as sensitizers are determined.