Novel nickel(II) coordination polymer based on a semi-rigid tricarboxylate acid ligand: synthesis, structure, and fluorescence recognition of acetylacetone in aqueous media

•A new luminescent Ni(II)-CP was constructed from a semi-rigid tricarboxylate acid.•The sensing property toward Hacac was mainly investigated.•The probable sensing mechanisms are also studied in more detail. Through a solvothermal reaction between the corresponding nickel(II) sulfate, π-electron rich tri-carboxylate ligand 4-(2′,3′-dicarboxylphenoxy) benzoic acid (H3L) and 1,2-bis (4-pyridyl) ethylene (bpe) molecule, a novel three-dimensional (3D) nickel-based coordination polymer (Ni-CP), namely [Ni3(L)2(bpe)3(H2O)4]·(H2O)6 (1) was successfully constructed. The structure was established by single-crystal X-ray diffraction, which reveals that 1 features a new 3,4,4-connected topology with the point symbol of (105·12) (4·102)2 (4·85)2. Subsequently, some studies on optical properties of compound 1 were carried out. Interestingly, the results suggest that compound 1 exhibits excellent applications as a fluorescent sensor for the recognition of Hacac via a fluorescence quenching approach. The detection limit can be as low as 10.19 µM. The possible mechanisms of the fluorescence turn-off effect were also discussed in detail. This work presents a case for monitoring Hacac concentrations in water samples. [Display omitted]