Fluorescent Sensing of Cesium Ions by an Amide-Linked BODIPY Dye: Synthesis and Photophysical Properties

Abstract

In this study, a new fluorescent sensor for Cs+ ion was designed and synthesized from the combination of pyridine-2,6-dicarboxamide and 4,4-difluoro-4-borata-3a,4a-diaza-s-indacene (BODIPY) scaffolds. The sensing capability of the target compound against a variety of ions was investigated. The structure of the target compound was proved by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and H-1 and (CNMR)-C-13 spectroscopies. Photophysical properties of the amide-linked BODIPY compound were studied by utilizing fluorescence spectroscopies in DMSO/water (9:1, v/v) solution. It was found that the final amide-linked BODIPY compound showed exclusively selective and sensitive turn-off sensor behavior for Cs+ ion over other metal ions (Li+, Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Hg2+, Pb2+, Mn2+, Cd2+, Ag+, Ni2+, Cu2+, Zn2+, Co2+, Cr3+ and Fe3+). The addition of Cs+ resulted in quenching of fluorescence intensity and the detection limit was calculated to be 0.273 mu M. According to Job's Plot, binding stoichiometry ratio of the target compound with Cs+ was 1:1.