Colorimetric chiral fluorescent sensors for Eu3+ and sequential enantioselective sensing of malate anion.

Abstract

Novel phenanthroline Schiff base fluorescent sensors L1, L2, and D1 were designed and synthesized. The sensing abilities of the compounds in the presence of metal cations (Li+ , Na+ , K+ , Ag+ , Mg2+ , Ba2+ , Ca2+ , Mn2+ , Pb2+ , Hg2+ , Ni2+ , Zn2+ , Cd2+ , Co2+ , Cu2+ , Cr3+ , Fe3+ , Fe2+ , Al3+ , and Eu3+ ) were studied by UV-vis and fluorescent spectroscopy. The compounds L1, L2, and D1 could act as Eu3+ ion turn-off fluorescent sensors based on ligand-to-metal binding mechanism in DMSO-H2 O solution (v/v=1:1, 10mM Tris, pH=7.4). Additionally, the L1-Eu3+ and D1-Eu3+ complexes could be applied as turn-on enantioselective sensors sensing of malate anion isomers with color changes. Furthermore, biological experiments using living PC-12 cells demonstrated that L1 and D1 had excellent membrane permeability and could be used as effective fluorescent sensors for detecting Eu3+ and malate anion in living cells.