A dual-chemosensor based on Ni-CP: Fluorescence turn-on sensing toward ascorbic acid and turn-off sensing toward acetylacetone

One new nickel(II)-based coordination polymer (CP), formulated as [Ni(HL)(bpe)(1.5)(H2O)] (compound 1; H3L = 5-(3,4-dicarboxylphenoxy) nicotic acid; bpe = 1,2-bis (4-pyridyl) ethylene) was successfully synthesized with a fluorescent semi-rigid tricarboxylate ligand H3L. 1 presents a unique 2D layer structure with (3, 4)-connected (4.7.8) (4(7).4(8)) topology. Fluorescence measurements reveal that 1 exhibits great fluorescence properties and excellent water stability. Significantly, compound 1 could be served as a dual-responsive fluorescent sensor to trace ascorbic acid (AA) and acetylacetone (acac) through fluorescent turn-on and turn-off, respectively. Both proposed sensing systems show good selectivity, sensitivity and anti-interferential performance. The limits of detection (LOD) for AA and acac are found to be 1.23 mu M and 3.54 mu M, respectively. Furthermore, the possible fluorescence sensing mechanisms have been also discussed in detail by Powder X-ray diffraction (PXRD) pattern, UV-vis spectroscopy and fluorescence lifetime measurements and density functional theory (DFT) calculations.

Automated summary

A new nickel(II)-based coordination polymer with a unique 2D layer structure was successfully synthesized. The polymer exhibits excellent fluorescence properties and water stability. It can be used as a dual-responsive fluorescent sensor for detecting ascorbic acid and acetylacetone.