Bodipy-based quinoline derivative as a highly Hg²⁺-selective fluorescent chemosensor and its potential applications

A highly efficient sensor has been successfully developed using quinoline-based BODIPY compounds (8-quinoline-4,4-difluoro-4-boro-3a, 4a-diazaindacene (C1) and 7-hydroxy-8-quinoline-4,4-difluoro-4-boro-3a, 4a-diazindacene (C2) to detect Hg²⁺ ions. The sensor C1 exhibits remarkable selectivity in detecting Hg²⁺ with a limit of detection 3.06 × 10^-8 mol/L. The developed chemical sensors have shown stability, cost-effectiveness, ease of preparation, and remarkable selectivity towards Hg²⁺ ions compared to other commonly occurring metal ions. The total recovery of the sensor C1 can be achieved by using a 0.1 mol/L solution of KI. The proposed sensor C1 has been applied to determine Hg²⁺ in tap and distilled water, yielding excellent results. In addition, the binding mode of C1-Hg²⁺ and C2-Hg²⁺ complexes was a 1:1 ratio confirmed by mass spectra, Job's plot, and DFT study. Moreover, the sensor C1 successfully applied for the biological studies results in negligible cytotoxicity, which demonstrates it can be used to determine Hg²⁺ in HT22 cells.