The Position of ‘Proton Transfer’ Phenomena in Case of Fluoride Detection: A Minireview

Abstract

Fluoride ion possessing substantial biological importance demands widespread applications on the basis of physiological and detrimental effects on human body and environmental aspects. Therefore, attractive attention has been paid by the researchers to reach the utmost stage of development of versatile colorimetric and fluorometric fluoride ion sensors. For this purpose, proton transfer phenomenon is an excellent pathway to trigger the recognition of fluoride ion using various kinds of sensor molecules. A strong mode of binding interaction between the chemosensor and F⁻ ion was streamlined in terms of colorimetry, fluorometry and NMR- and DFT-based theoretical studies. This minireview article summarizes the recent development of various fluoride sensors based upon the proton transfer–mediated signalling mechanisms, namely, hydrogen bonding–promoted proton transfer, excited state intermolecular proton transfer (ESPT) and excited state intramolecular proton transfer (ESIPT).