New Hg2+-selective chromo- and fluoroionophore based upon 8-hydroxyquinoline

A new 8-hydroxyquinoline derivative having an appended borondipyrromethene function has been prepared, and its metal ion sensing properties were investigated. The designed compound exhibited pronounced Hg2+-selective on-off-type fluoroionophoric properties among the representative transition- and heavy-metal ions in aqueous dioxane solution. The fluorescence was efficiently quenched more than 98% with 5 equiv of Hg2+ ions, and the detection limit was found to be 5 x 10(-6) M in a dioxane-water (1:3, v/v) solvent system. The ionophore also showed a selective chromogenic behavior toward Hg2+ ions by changing the color of the solution from light amber to red, which can be detected with the naked eye.