Improving Ion Selectivity of 1,4,7-Triazacyclononane-Based Receptor by Zinc Coordination: “Turn-On” Chemosensor for Br<sup>–</sup> and Fe<sup>3+</sup> Ions
Meihua Lin, Xiaoxia Ren, Xiao‐Min Ning, Dongyang Liu, Jing Qian
Abstract
Ion-responsive probes have gathered significant attention because of health and environmental factors, but there are few reports on the “turn-on” mechanism of Fe3+ and sensitive detection of Br– by fluorescence measurement. Herein, a green luminescence material, N-5-acetyl-2-hydroxy-benzamide-1,4,7-triazacyclononane (btacn), was successfully synthesized for the first time and comprehensively characterized. As expected, btacn exhibits high sensitive, but nonspecific, extensive interaction with Cu2+, Co2+, Zn2+, Mn2+, and Fe3+ ions. Therefore, to improve the specificity of the probe, we tried to synthesize transition metal complexes of btacn, but all failed except Zn(btacn)Cl2. In addition, the preformed complex, Zn(btacn)Cl2, was used as a special “turn-on” chemosensor for detecting trace amounts of Br– and Fe3+. The electrostatic interaction with Fe3+ and the hydrogen bond of PhO-H···Br– leads to obvious changes in the electronic cloud of Zn(btacn)Cl2, which are reflected in different spectral responses.