Hydrogen bond regulated hydrogen sulfate ion recognition: an overview

Abstract

Hydrogen sulfate possesses substantial biological importance, having a colossal impact on physiological and environmental events. Therefore, several scientific groups have devoted serious effort to the development of versatile colorimetric and fluorimetric HSO₄⁻ sensors. Along with the scope, challenges, and significance, this review emphasizes the advancement of the optical recognition of HSO₄⁻ based on hydrogen bonding during the past two decades. Moreover, hydrogen-bond-driven proton transfer, ESIPT, ICT, PET, CHEF, and TBET mechanisms that allow for the optical detection of HSO₄⁻ are also discussed concisely. The foundation of this review includes the key points of the sensing process, like the nature of spectroscopic changes, selectivity and sensitivity, naked-eye color changes, the reusability of sensors, and the in vivo detection of HSO₄⁻, if any. Special attention is focused on the correlation between the photophysical changes and the underlying interaction mechanisms that triggered the recognition aspect.