Iodine‐DMSO Catalyzed β‐carboline Derivative Chemoselective Fluorescent Molecule for Detection of Fluoride and Cyanide Anion

Abstract

AbstractIn this work, a simple and highly sensitive fluorescent receptor 1‐(p‐tolyl)‐4,9‐dihydro‐3H‐pyrido[3,4‐b]indole (receptor 1), has been synthesized for the detection of fluoride and cyanide ions. The receptor 1 was very selective towards fluoride and cyanide anions over other anions such as Cl−, Br−, I−, HSO4−, NO3−, HPO42−, and OAc−. Synthesized receptor 1 shows low detection limits 3.29 × 10−8 M for fluoride ion, which was determined by UV–vis absorption. While LOD for cyanide was observed to be 61.5 nM. Importantly, while, receptor 1 produced binding constant for fluoride and cyanide in DMSO‐H2O (1:9, v/v) was found to be 5 × 10−4M−1 and 3.28 × 10−5 M−1, respectively. The variation in the optical and fluorescence spectroscopy confirms the formation of N─H⋯F− and N─H⋯CN− hydrogen bond of the pyrrolic proton The sensing mechanism displayed by receptor 1 for fluoride and cyanide ions was confirmed by 1H‐NMR and FT‐IR spectroscopic along with density functional theory (DFT) calculations. Solution with the fluoride and cyanide ions in DMSO‐H2O (1:9, v/v) shows a color change from light yellow to blue under UV light and yellow to colorless in visible light.