Design and Synthesis of a Dinuclear Copper(II) Probe for Selective Fluorescence Sensing of Pyrophosphate.

A novel coumarin-based compound DPAC with two dipicolylamine (DPA) arms as the chelator sites was designed and synthesized. The compound DPAC exhibits a highly selective response to Cu²⁺ ions with a distinctly emission-quenching phenomenon. Moreover, the in situ formed complex DPAC-Cu²⁺ was used for the detection of pyrophosphate (PPi). The binding manner of probe DPAC-Cu²⁺ with PPi in 1 : 1 stoichiometry was supported by the Benesi-Hildebrand fitting, ESI-MS and HPLC analysis. The linear range of PPi concentration was 1-4 μM, and the detection limit was 0.53 μM. The competing experiments illustrated that the probe DPAC-Cu²⁺ had good sensitivity and selectivity for PPi than other anions, including ATP, ADP, AMP, and Pi in CH₃CN : HEPES (3 : 2, v/v, pH=7.20) buffer. Further, cell fluorescence imaging experiments indicated that the probe DPAC-Cu²⁺ had a potential to be used to detect PPi in vivo. [ABSTRACT FROM AUTHOR]