Chromogenic and fluorogenic sensing properties toward cations and anions by a terpyridine/phenylimidazo [4,5-f]phenanthroline hybrid

A modified synthesis of terpyridine/phenylimidazo[4,5-f]phenanthroline hybrid 2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L) is reported. The optical and colorimetric sensing properties of L for cations and anions were investigated by naked eye, and UV-vis and fluorescence spectroscopy in CH3CN-N,N-dimethylformamide (43:1, v/v). L was shown to effectively and selectively recognize biologically important F− over Cl−, Br−, I−, AcO−, NO3−, ClO4−, and H2PO4−. L in CH3CN/N,N-dimethylformamide (43:1, v/v) was also found to have fluorimetric sensing ability for Zn2+ and Cd2+. In both the CH3CN/N,N-dimethylformamide and aqueous 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer (pH = 7.2)/CH3CN/DMF (13/30/1, v/v/v) solutions, L exhibited colorimetric sensing ability for Fe2+ by an obvious color change from colorless to magenta.