Design and Synthesis of Fluorescent Sensors for Zinc Ion Derived from 2‐Aminobenzamide

Four novel Zn2+ fluorescent sensors have been designed with N,N‐bis(2‐pyridylmethyl)ethylenediamine as chelator and 2‐aminobenzamide as fluorophore. These sensors were prepared in two or three steps from readily available starting materials. Of the four designed sensors, ZnABA was found to be the most efficient Zn2+‐specific fluorescent probe and has good solubility in biological buffer, a large Stokes shift (186 nm), a high off–on fluorescence response (16‐fold enhancement), and distinct selectivity towards Zn2+ over other metal ions. Our results have demonstrated an excellent linear relationship between the fluorescence intensity of ZnABA and the Zn2+ concentration from 0 to 10 μM, which indicates that ZnABA has the potential to be used for the quantitative determination of Zn2+ in an aqueous environment.