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

Abstract 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 HSO 4 − anion whereas other physiologically and environmentally important anions such as F − , Cl − , Br − , I − , CN − , OAc − , HCO 3 − , H 2 PO 4 − , NO 3 − , NO 2 − and SO 4 2− 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.