LAUSR

A new and efficient fluorescent sensor 4′-hydroxy-3′-[(4-antipyrineimino)methyl]-4-biphenylcarboni- trile(L) was prepared for the selective detection of Zn2+ in aqueous ethanol medium. When excited at 419 nm, the fluorescent intensity of sensor L at 507 nm was remarkably increased more than 54-fold after adding Zn2+ ions. The strong green emission of the solution can be easily identified by naked eye under UV light. Thus, sensor L behaves as a naked eye fluorescent “turn on” detector for Zn2+ ions. The fluorescence enhancement might be attributed to the inhibition of excited state intramolecular proton transfer(ESIPT) and C=N isomerization as well as the chelation enhanced fluorescence(CHEF) effect. The complex solution of sensor L with Zn2+ ions exhibited reversibility with ethylene diamine tetraacetic acid(EDTA) and the probe could be recycled for further use. Notably, sensor L could clearly distinguish Zn2+ from Cd2+. The interaction of sensor L with zinc ions was investigated by means of FTIR, 1H NMR and HRMS spectroscopy. Furthermore, sensor L has been applied for cell imaging studies.