A novel iodination-triggered competitive coordination mechanism: Indirect detection of Hg²⁺ and I^- using a simple copillar[5]arene-based fluorometric sensor

A novel iodination-triggered competitive coordination has been developed for indirect detection of Hg²⁺ and I^- using the simple copillar[5]arene-based sensor DBP5. While DBP5 could directly sense neither Hg²⁺ nor I^-, the iodinated form of DBP5 detected Hg²⁺ with high selectivity and sensitivity (3.73 × 10^-8 mol L^-1). Other cations including Fe³⁺, Co²⁺, Ca²⁺, Ni²⁺, Pb²⁺, Cd²⁺, Zn²⁺, Cr³⁺, Mg²⁺ and Ag⁺ had no obvious influence on the probing behavior. In addition, a system consisting of Hg²⁺ in a DBP5 solution highly selectively and sensitively (3.51 × 10^-7 mol L^-1) detected I^- based on a combined iodination and Hg²⁺ coordination process. It is a novel and efficient way for detection Hg²⁺ and I^- in an aqueous solution. Moreover, the changes in the fluorescence of DBP5 resulting from the addition of Hg²⁺ and I^- were utilized to form a molecular NAND logic gate.