Highly Selective Chromogenic and Redox or Fluorescent Sensors of Hg²⁺ in Aqueous Environment Based on 1,4-Disubstituted Azines

Two new chemosensors that exhibit high affinity and high selectivity for Hg2+ in aqueous environment which operate through two different channels, optic/redox and optic/fluorescent, are reported. The optical change in sensing can be used even for a “naked-eye” detection of Hg2+ ions, whereas the fluorescent response can be modulated by varying the solvent polarity.