Recognition and visual detection of ADP and ATP based on a dinuclear Zn(II)-complex with pyrocatechol violet in water

The new fluorescent dinuclear complex [Zn2L(S)] 1, (asymmetric ligand, L = 5,8-Bis{[bis(acetate)amino]methyl} quinoline, S = solvent) was synthesized and studied in-depth as a receptor for nucleoside polyphosphates in 100% aqueous solution at physiological pH. The Zn-receptor 1 shows turn-on fluorescence and high selectivity to adenosine 5′-diphosphate (ADP) and adenosine 5′-triphosphate (ATP) over other phosphorylated anions including guanosine 5′-tripohosphate (GTP), citidine 5′-tripohosphate (CTP) and pyrophosphate. On the basis of the spectroscopic tools (1H, 31P NMR, UV–vis, fluorescence) and DFT calculations, the Zn-receptor binds ADP with high affinity (log K = 5.12) through three-point recognition involving cooperative coordination bonds and a hydrogen bond. The Zn-receptor 1 is an order of the magnitude more selective for ADP than ATP. ADP can be selectively detected in water even in the presence of coexisting species in blood plasma and urine with a detection limit of 30 μmol L−1 using a naked-eye detection system based on the complex between Zn-receptor 1 and pyrocatechol violet. [Display omitted] •A new dinuclear zinc complex 1, was designed, synthesized, and studied as a receptor for nucleoside polyphosphates.•The Zn-receptor 1 shows turn-on fluorescence and high selectivity to ADP and ATP over other phosphorylated anions.•ADP/ATP recognition was studied by spectroscopic tools (1H, 31P NMR, UV–vis, fluorescence) and DFT calculations.•ADP can be selectively detected by a visual color change using an assembly between the Zn-receptor 1 and pyrocatechol violet.