Historical overview and recent progress on supramolecular sensors for thorium recognition

A significant interest worldwide has been shown in developing a thorium (Th) fuel-based nuclear power program to supplement uranium reserves for future power generation. This has resulted in Th contamination in the biotic system due to overexploitation. Detection of Th4+ in actual samples and living systems has become vital. This review summarized the Th4+ sensors in terms of optical sensors (colourimetric, chromogenic, fluorogenic, and optodes), electrochemical sensors (potentiometric and potentiostatic), synthesis strategy, and theoretical studies. This review helps researchers from synthetic, analytical, and theoretical areas to design new synthetic routes and develop molecular sensors for Th4+. In contrast, analytical chemists and instrumentation engineers can provide new methods and interface with allied techniques. This review will be a good reference for the development of Th4+ sensor. •Azo dyes, hydrazides based Schiff base and organo-phosphine oxide major molecular sensors for Th4+ recognition.•Structure, analytical parameters, sensing mechanisms and applications of the sensors are discussed.•Future scope on designing of molecular sensors for Th4+ sensing is discussed.