A new 3D four-fold interpenetrated dia-like luminescent Zn(II)-based metal-organic framework: sensitive detection of Fe3+, Cr2O72-, CrO42- in water and nitrobenzene in ethanol

A new three-dimensional zinc-based metal-organic framework (MOF), namely, [Zn2(4,4′-nba)2(1,4-bib)2]n (1), where 4,4′-H2nba = 3-nitro-4,4′-biphenyldicarboxylic acid and 1,4-bib = 1,4-bis(imidazole-1-ylmethyl)benzene, has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric, and Hirshfeld surface analyses. In the crystal structure of 1, oxygen and nitrogen atoms of two 4,4′-nba2- and two 1,4-bib ligands bind to the metal ion, leaving an irregular tetrahedral geometry. The 4,4′-nba2- and 1,4-bib ligands serve as linear bidentate linkers to form a four-fold interpenetrated 3D framework with a dia-like topology. Luminescence studies revealed that 1 can be used as highly sensitive multi-responsive luminescent sensors for sensing Fe3+, Cr2O72- and CrO42- in H2O and nitrobenzene in C2H5OH. The detection limits of Fe3+, Cr2O72-, CrO42- and nitrobenzene can reach 1.76 µM, 3.25 µM, 3.8 µM, and 0.19 µM, respectively. Moreover, 1 can be recycled at least five times for sensing Fe(III) and Cr(VI). The sensitive and stable ability of 1, 1@Fe3+, 1@ Cr2O72-, and 1@CrO42- were also investigated at different pH and temperature. 1 exhibited satisfactory sensing abilities when the pH was ranged from 3 to 10, and the temperature from 5℃ to 75℃, indicating that 1 could act as a fluorescent probe for Fe3+ under physiological pH conditions. These results support that 1 has good anti-interference ability and potential application for sensing Fe(III), Cr(VI) and nitrobenzene in real environments. In addition, the possible fluorescence quenching mechanism was explored in this paper.