Ammonium-bearing dinuclear copper(II) complex: a highly selective and sensitive colorimetric probe for pyrophosphate.

Two dinuclear copper complexes with and without ammonium moieties were synthesized. The complexes exhibited selective binding affinity to pyrophosphate in aqueous solution. The dinuclear copper complex, with ammonium arms, showed a ca. 527-fold enhancement in pyrophosphate binding affinity compared with its analogue without ammonium units.