Precision detection of cyanide, fluoride, and hydroxide ions using a new tetraseleno-BODIPY fluorescent sensor

Abstract

A new chemosensor based on Seleno-BODIPY (4) was designed and synthesized for the rapid and sensitive detection of CN–, F−, and OH– ions in THF, exhibiting ultra-low detection limits of 26.26 nM, 43.05 nM, and 8.64 nM, respectively, through a turn-on fluorescent process. The seleno-funcionalization step was based on a novel methodology developed by our group, allowing direct functionalization of the BODIPY core. This procedure involves a quick reaction utilizing Ph2Se2 as a selenium source, BPO (benzoyl peroxide), and p-TSA (p-toluenesulfonic acid) in acetonitrile, enabling the production of the corresponding chalcogenated BODIPYs containing one to four selenium groups, demonstrating its versatility. The structure of BODIPY 4 was confirmed by HRMS, 1H, 13C, 77Se NMR, and IR spectra, and its photophysical properties were also evaluated. BODIPY 4 was applied to detect CN–, F−, and OH– ions in dual-mode detection (UV–Vis and fluorescence spectra), displaying a ratiometric response. The new probe exhibited a fast response time, visual color change from blue to fluorescent yellow, and high sensitivity and selectivity for these analytes over other selected anions. Mechanistic investigation through mass analysis revealed that the detection of these anions by BODIPY 4 occurs via an Aromatic Nucleophilic Substitution reaction with phenylselenide as the leaving group.