Hg2+-selective Fluorogenic Chemosensor Derived from 8-Aminoquinoline

8-Aminoquinoline-based benzothiazole derivative 3 showed distinctive Hg2+-selective fluoroionophoric properties over other transition metal ions. The fluorescence emission at 580 nm was completely quenched upon complexation with 100 equiv. of Hg2 + ions in dioxane–H2O system (9:1, v/v) and the selectivity was found to be Hg2+ > Cu2+ > other representative transition and heavy metal ions.