Zn2+ fluorescent chemosensors and the influence of their spacer length on tuning Zn2+ selectivity†
Abstract
Zn2+ fluorescent chemosensors based on the chelation-enhanced fluorescence (CHEF) mechanism were prepared and fine-tuning of their Zn2+ selectivity was achieved by control of the spacer length. The fluorescence emission response to metal ions shows a fluorescence decrease for Co2+, Cu2+ and Ni2+ and an increase for Ca2+, Cd2+ and Zn2+. Maximum Zn2+ selectivity over Ca2+ and Cd2+ was achieved with 3. The basic binding properties (stoichiometry, apparent dissociation constant, and pH dependence) were measured by