1-Pyrenyl- and 3-Perylenyl-antimony(V) Derivatives for the Fluorescence Turn-On Sensing of Fluoride Ions in Water at Sub-ppm Concentrations

Abstract

In the context of our work on main group-based anion sensors, we have synthesized the bromide salts of a series of tetraarylstibonium cations of general formula [ArSbPh3]+ with Ar = 9-phenanthryl ([1]+), 1-pyrenyl- ([2]+), and 3-perylenyl ([3]+). While [1]+ is not stable in water, we found that [2]+ and [3]+ can be used as sensors for the sub-ppm detection of fluoride anions in aqueous solutions consisting of 9/1 (v/v) H2O/DMSO (pH 4.8). Fluoride sensing, which rests on the formation of the fluorostiboranes 2–F and 3–F, is accompanied by a distinct turn-on fluorescence response. This response is especially marked upon conversion of [3]+ into 3–F, with a fluorescence intensity enhancement by ∼8 fold and a quantum yield of 59.2% for 3–F. The relevance of this study is established by demonstrating that [3]+ can be used as a selective fluoride sensor for bottle or tap water.