Turn-Off Fluorescence Sensing of Benzenediols via Guest-Induced π-Conjugation Switching in Bisimidazole-Based Hydrindacene Allosteric Receptors

Abstract

Fluorescent bisimidazole-based hydrindacene allosteric receptors 1a-c and 2 were synthesized for nonlinear ON/OFF sensing of benzenediols. By tuning their D-π-D conjugation through substituent modification, these receptors were designed to function as turn-off fluorescent sensors based on the cleavage of their π-conjugation accompanied by binding with benzenediols. The cooperative allosteric binding demonstrated selective and efficient nonlinear quenching toward orcinol.