An Automatic Molecular Dispenser of Chloride

Abstract : The combined activity of the 1.1.1-cryptand and of a dicopper(II) bistren cryptate complex including chloride makes the Cl- ion be continuously and slowly delivered to the solution, without any external intervention. The 1.1.1-cryptand slowly releases OH- ions, according to a defined kinetics, and each OH- ion displaces a Cl- ion from the cryptate. Chloride displacement induces a sharp colour change from bright yellow to aquamarine and can be conveniently monitored spectrophotometrically, even in diluted solutions. The 1.1.1-cryptand is the motor of a molecular dispenser (the dicopper(II) cryptate) delivering chloride ion automatically, from the inside of the solution.