Synthesis And Luminescent Properties Of New Type Rare Earth Metal Organic Framework Materials

Lanthanide metal-organic frameworks（Ln-MOFs）have great development potential in the field of sensing materials due to their unique luminescence characteristics,high luminescence quantum yield,long fluorescence lifetime and large Stokes shift.Ln-MOFs have multiple luminescence response sites based on lanthanide ions and organic ligands,which enriches the detection range of analytes such as inorganic anions and cations,explosives,and antibiotics.At the same time,due to the similarity of lanthanide ions,uniform mixed lanthanide Ln-MOFs,especially Tb/Eu-MOFs,can be formed to prepare dual emission fluorescent probes with self-calibration capability.In this work,based on three kinds of functionalized ligands,we have afforded a series of Ln-MOFs and evaluated their potential applications as chemical sensors.1.Dual-Functional Ln-MOFs based on a Zwitterionic Ligand as Ratiometric Thermometer and Selective Sensor for Nitroaromatic ExplosivesA family of lanthanide-organic frameworks,[Ln₂（L）₃·NO₃]·（NO₃）₂·xsolvent[Ln³⁺=Eu and Tb,H₂L-Cl=N-（4-carboxybenzyl）-4-（4-carboxyphenyl）pyridinium chloride]have been synthesized and structurally characterized.The obtained Eu³⁺/Tb³⁺-mixed Tb_99.9/Eu_0.1-MOF can be served as a ratiometric temperature sensor with a good linear response from 257 K to 397 K.For the strong luminescence and good water-stability,Eu-MOF can be exploited as a selective and efficient sensor for detecting nitroaromatic explosives.2.Chemical and temperature sensors based on lanthanide post-synthetic modification of sulfone/phospherous groups functionalized MOFIn this work,based on the mixed-ligand strategy,an unusual[Cd₃（tpo）₂（bims）]?xsolvent with coordination-free sulfone and phosphorous groups has been synthesized and structurally characterized.Lanthanide ions(Eu³⁺,Tb³⁺)were introduced through post-synthesis modification.These compounds have been characterized by infrared spectroscopy,X-ray powder diffraction and thermogravimetric analysis.For their good thermal/water stability and optical properties,these can be used as selective and efficient detection sensors for trace TNP.At the same time,the obtained dual-metal Eu_0.14/Tb_0.86-MOF can be used as a ratiometric temperature sensor,which has a good linear response in the range of107-277K.3.Chemical sensors based on Eu³⁺post-synthetic modification of a new Ui O-67analogueBased on sulfone-tagged dibenzo[b,d]thiophene-3.7-dicarboxylic acid5,5-dioxide,an Ui O-67 type metal-organic framework has been synthesized and structurally characterized.Eu³⁺was introduced through post-synthesis modification to afford Eu³⁺@Ui O-67-SO₂.For its good water stability and optical properties,Eu³⁺@Ui O-67-SO₂ can be used to detect Cr₂O₇^2-and TNP.For the detection of Cr₂O₇^2-,the calculated Ksv value is 9.65×10⁴ M^-1,and the detection limit is 74 nM.In the detection of TNP,the calculated Ksv value is 0.41×10⁴ M^-1,and the detection limit is 39 nM.