Construction of a stable Zn(II)-MOF based on mixed ligand strategy for fluorescence detection of antibiotics and Fe3+ ions

A stable Zn(II)-MOF ([Zn(L-1)(0.5)(L-2)(0.5)(H2O)]center dot DMF HBU-19, L-1 = 2,3,5,6-tetra(4-carboxyphenyl)pyrazine, L-2 = 1,2-di(4-pyridyl)ethylene) was synthesized by solvothermal method based on mixed ligand strategy. Crystal structure analysis showed that HBU-19 was a three-dimensional structure. PXRD and TG characterization indicated that HBU-19 possessed high phase purity and good thermal stability. HBU-19 can selectively detect two different antibiotics (nitrofurazone, NFZ and nitrofurantoin, NFT) simultaneously in aqueous media by fluorescence quenching. The detection limits are 19.6 mu M and 17.9 mu M, and the corresponding quenching coefficients are 5.2 x 10(4) M-1 and 5.5 x 10(4) M-1. In addition, HBU-19 exhibits a detection limit of 3.4 mu M and a quenching coefficient of 2.24 x 10(5) M-1 for Fe3+ ions. The anti-interference experiments revealed that the compound showed good recognition selectivity. The possible sensing mechanisms have been also discussed in detail. Therefore, HBU-19 may be a promising sensor for detecting NFZ, NFT, and Fe3+ ions of wastewater.