3‐Pyrrolyl BODIPY Based Schiff Base Fluorophores: A Selective Chemodosimetric and Optical Sensor for Diethyl Chlorophosphate

Abstract

AbstractDiethyl chlorophosphate (DCP), an organophosphate, is utilized as a pesticide, herbicide, and for various other applications. Despite many uses of organophosphates, the organophosphates are noxious and harmful substances, and their selective detection is a critical concern in the context of the environment, physiology, and social security. In a methodological quest, here we have synthesized two Schiff base compounds 1 and 2 by introducing the hydroxyl group at the α‐position of 3‐pyrrolyl BODIPY either directly as hydroxylamine 1 or at the ortho position of aryl ring as 2‐aminophenol 2. Both compounds 1 and 2 exhibited high selectivity and high sensitivity for DCP over other pesticides in the aqueous‐alcoholic medium at physiological pH. This occurs via nucleophilic phosphorylation of the hydroxyl group, which resulted in both compounds exhibiting two different optical signals following the structure‐function correlation of the pyrrolyl BODIPY systems. Upon binding DCP, compound 1 showed a quenching in the optical spectrum because of phosphorylation of hydroxyl group whereas compound 2 exhibited enhancements in both absorption and fluorescence spectra because of hydroxyl phosphorylation followed by intramolecular cyclization. Furthermore, the fluorescent microscopy experiments also indicated that the compound could be used as a fluorescent compound for sensing DCP in plant tissues.