Design,Synthesis And Fluorescence Sensing Of Lanthanide Metal-Organic Framework Materials Based On Carboxylate、Sulfonate Aryl Ether Ligands

Lanthanide metal-organic framework materials based on carboxylate acid aromatic ether ligands have been widely used in fluorescence sensing,catalysis,adsorption and many other fields due to their host-guest interaction sites and excellent optical properties.In this paper,a series of lanthanide metal-organic framework materials were designed and synthesized using carboxylate acid aromatic ether ligands,and the potential applications of the materials as fluorescent probes are explored.The research of this thesis includes the following four aspects:（1）Three isostructural tetranuclear lanthanide metal-organic framework materials[Ln₄L₆·DMF]were synthesized by the reaction of carboxylate acid aromatic ether ligand（L1）with rare earth nitrates,where Ln is Eu（1）,Tb（2）,Sm（3）.Single crystal test shows that MOF 1 belongs to monoclinic system,P2₁/c space group.The optical sensing studies of the materials show that MOF 1 and 2 can be used for the detection of UO₂²⁺in DMF.The detection limits are 0.14μM and 0.42μM,and the Ksv values are 2.45×10⁴M^-1 and 1.25×10⁴ M^-1,respectively.Through anti-interference and titration experiments,it was found that MOF 1 and 2 have high sensitivity,low detection limit and fast response time,and have potential application prospects in UO₂²⁺.（2）[(E u N a _0.5L ₂)·N a_0.5·D M F·3.5 H₂O]_n（M O F 4）and[(Eu Li_0.5L₂)·Li_0.5·DMF·3.5H₂O]_n（MOF 5）were synthesized by one-pot solvothermal method using carboxylate aryl ether ligands（L1）,europium nitrate,sodium chloride or lithium chloride.Single crystal tests show that MOF 4 and 5 belong to tetragonal system,I4₁/acd space group.One-dimensional helical chains and three-dimensional frame structures are formed by trinuclear metal cluster units.Since the oxygen-rich atoms distributed on the inner surface of the channel can be used as accessible Lewis base response sites to recognize UO₂²⁺ions,the optical sensing studies of the materials show that MOF 4 and 5 can quickly detect UO₂²⁺in water.The detection limits are 72.7 n M and 0.24μM,and the Ksv values are 3.66×10⁴ M^-1 and 2.20×10⁴ M^-1,respectively.The detection limit of MOF 4 in lake water was 113.0 n M,which was lower than the maximum concentration of 130.0 n M in drinking water recommended by EPA.The experimental results show that the sensor has excellent selectivity and sensitivity,and has broad application prospects in real life detection.（3）Two new three-dimensional framework materials were obtained by coordinating rare earth ions[Eu³⁺（6）,Tb³⁺（7）]with sulfonic acid-carboxylic acid organic ligands.The single crystal tests of MOF 6 and MOF 7 show that the two materials are isomorphic and have square pores and a large number of uncoordinated sulfonic acid groups in the pores.MOF 6 and MOF 7 can detect UO₂²⁺in water with detection limits of 0.45μM and 5.29μM,and Ksv values of 1.07×10⁴ M^-1 and 1.72×10⁴ M^-1,respectively.