Fluorescent detection of phosphate anion by a highly selective chemosensor in water

A macrocyclic dinuclear copper complex, [Cu2II(1)Br4]·2H2O has been synthesized and characterized by X-ray crystallography, in which each metal ion is pentacoordinated in a square pyramidal environment and the macrocycle is folded to form a boat-shaped empty cavity. As studied by an indicator displacement assay, the dinuclear complex shows strong selectivity for phosphate over sulfate, nitrate, perchlorate and halides in water at physiological pH.