Water-stable nickel-based coordination polymer for selective and sensitive enhancing and quenching fluorescence sensing of ascorbic acid and acetylacetone

Abstract

The novel Ni-based coordination polymer [Ni(H2edda) (bpe)] (CP 1) was successfully synthesized by employing 5,5′ (ethane-1,2-diylbis(oxy)) diisophthalic acid (H4edda) and 1,2-bis (4-pyridyl) ethylene (bpe) under hydrothermal conditions. Structural analysis indicates that CP 1 presents a 2-fold-interpenetrated two-dimensional (2 D) framework with a uninodal sql topology. Further investigation reveals that the newly obtained CP can be stable in water or even exposed in a certain acid/base aqueous solution (pH = 3–11) for a long period of time. Remarkably, CP 1 can further serve as a bifunctional sensor for ascorbic acid (AA) and acetylacetone (acac) in aqueous media according to fluorescence enhancing and quenching effects, respectively. Notably, both sensing processes are labeled with exceptional anti-interference property, high sensitivity and selectivity, wide linear range (0–50 μM for AA and 0.2–1.8 mM for acac) and low detection limit (1.37 nM for AA and 1.58 μM for acac). Theoretical simulations and experimental findings point out that in the process of AA detection by CP 1, the significant fluorescence enhancement could be caused by the photo-induced electron transfer (PET) process, while the inner filter effect (IFE) mechanism combined with PET should be responsible for the fluorescence quenching of CP 1 by acac.