Construction Of Zn(Ⅱ) And Tb(Ⅲ) Metal-organic Frameworks And Their Fluorescence Sensing Of Water Pollutants

With the continuous increase of the world’s population and the continuous improvement of people’s living standards,people pay more and more attention to the safety of the environment and food.The effective monitoring of pollutants in the environment and food is an urgent problem to be discussed.Therefore,it is of great research value to build a high sensitivity,good selectivity,simple and convenient,recyclable and accurate detection system.As a detection system with quick response,convenient operation and high visualization,fluorescent probe has been widely used to explore the detection of pollutants.In this study,two fluorescence probes with good stability were constructed by hydrothermal method based on metal-organic frameworks（MOFs）for the identification of pollutants（Nicosulfuron,Thiamethoxam,Nitrofurazone,Furazolidone）.The two fluorescent probes belong to single-emission and multi-emission fluorescent probes respectively,and they have the advantages of good stability,fast response,excellent anti-interference ability and repeatability.The specific research contents are as follows:1.Firstly,2’-amino-[1,1’:4’,1’’-terphenyl]-4,4’’-dicarboxylic acid（H₂TPDC-NH₂）was used as an organic ligand and Zn（NO₃）₂·6H₂O was used as a metal node to construct a two-dimensional metal-organic framework fluorescent probe（Zn-TPDC-NH₂）with good stability.The structural formula is（[Zn（TPDC-NH₂）（DMF）]_n）.Its structure and stability were characterized and analyzed by PXRD,FTIR and TGA.The fluorescence probe was used to detect different kinds of antibiotics by fluorescence analysis.Zn-TPDC-NH₂ emits blue light at 469 nm under excitation of 388 nm and shows specific recognition of the antibiotics Nitrofurazone（NFZ）and Furazolidone（FZD）.Detection limits as low as 0.62 and1.08μM.It has good anti-interference and circulation ability2.A water-stabilized lanthanide MOFs fluorescent probe（Tb-BDOA）was synthesized by hydrothermal method using benzene-1,4-dioxyacetic acid（H₂BDOA）as the organic ligand and Tb（NO₃）₃·6H₂O as the metal node.The structure formula is[Tb₄（BDOA）₂（μ₃-OH）₈（H₂O）₃]_n.Several emission peaks were used for self-calibration detection of pesticides.Tb-BDOA emits green fluorescence at 445 nm,488 nm,545 nm,587 nm and 621 nm under the excitation of 280 nm.Different pesticides will cause different changes in the emission peaks of Tb-BDOA,so Tb-BDOA can conveniently distinguish different pesticides and display self-calibration fluorescent response to nicosulfuron（NSF）and thiamethoxam（TMT）.Besides the unique combination of each pesticide and ligand→Tb³⁺emission intensity ratio showed significant correlation,which realized specific two-dimensional fingerprint recognition.At the same time,3D code recognition is realized by drawing the changes of two ratios under different concentrations.In general,Tb-BDOA as a proportional self-calibration fluorescent probe has good stability,high selectivity and good reproducibility.