An abiotic receptor and its Cu(II) complex as selective ‘turn-off’ chemosensor for bisulfate ion

• 2,6-bis[(N-Phenyl)amido]-4-methylphenol and its copper(II) complex.
• Their anion recognition behavior.
• Turn-off fluorescence sensor for the bisulfate anion.
• Stern–Volmer plot and life-time measurement.
• Both static and dynamic emission quenching processes.

The ligand 2,6-bis[(N-phenyl)amido]-4-methylphenol (receptor 1) and its copper(II) complex (receptor 2) having amide moiety have been designed and synthesized for selective sensing of anions. The anion recognition behavior of the receptor 1 and its copper complex (receptor 2) has been studied in acetonitrile. Quenching of fluorescence was observed for both receptors in presence of HSO4− anion whereas other physiologically and environmentally important anions such as F−, Cl−, Br−, I−, CN−, OAc−, HCO3−, H2PO4−, NO3−, NO2− and SO42− show fluorescence enhancement behavior. The sensing protocol has been studied both spectrophotometrically as well as spectrofluorometrically. Fluorescence quenching is suggested to proceed via both dynamic and static processes.

Amide-based receptor 1 and its copper(II) complex (receptor 2) for selective fluorescence sensing of anions. Both receptor 1 and 2 exhibit ‘turn-off’ behavior in the presence of HSO4− anions. The sensing protocol has been suggested to proceed via a static emission quenching process.Figure optionsDownload as PowerPoint slide