Synthesis And Luminescence Sensing Property Of Europium(Ⅲ) And Terbium(Ⅲ) Metal-Organic Coordination Polymers

Lanthanide metal-organic coordination polymers possess narrow emission peaks,high purity color and long luminescence lifetimes,which demonstrates potential applications in the field of chemosensors,visualization of latent fingerprints and so on.However,it remains a problem that lanthanide metal-organic coordination polymers have relatively low selectivity and sensitivity.In addition,the bioluminescence of the substrates will interfere with the visualization process.In terms the of aforementioned problems,europium（Ⅲ）and terbium（Ⅲ）ions were chosen as metal centers to assemble with 1,2,4,5-benzenetetracarboxylic acid and2,5-thiophenedicarboxylic acid as organic ligands under solvothermal conditions.Lanthanide coordination polymers and series of bimetallic lanthanide coordination polymers with two-dimension and three-dimension were obtained.Crystal structures and photophysical property were characterized with their sensing properties towards metal ions and anion investigated.Their potential application in visualization of latent fingerprints were further explored.The main contents of this thesis are as follows:（1）Synthesis,crystal structure and sensing property of two-dimensional europium metal-organic coordination polymer.A two-dimensional lanthanide metal-organic coordination polymer[Eu（BTEC）_0.5（HCOO）（H₂O）₂]（compound 1）was synthesized based on1,2,4,5-benzenetetracarboxylic acid and europium（Ⅲ）ion via solvothermal method.When dispersed in DMSO solution,compound 1 can detect Cu²⁺and Fe³⁺ions.The quenching percentage for Cu²⁺and Fe³⁺were 90.74%and 91.99%,respectively.When dispersed in aqueous solution,compound 1 can be used to sense Fe³⁺ions and the quenching percentage was calculated to be 93.01%.XRD,EDS,UV-vis absorbance and fluorescence lifetime were applied to investigate the sensing mechanism.（2）Synthesis,crystal structure and sensing property of three-dimensional europium（Ⅲ）and terbium（Ⅲ）coordination polymers.Two isostructural lanthanide metal-organic coordination polymers[Eu₂（TDC）₃（DMA）₂]（compound 2）and[Tb₂（TDC）₃（DMA）₂]（compound 3）were obtained based on 2,5-thiophenedicarboxylic acid by solvothermal method,which possess similar sensing properties in that both of them can detect phosphate ions and citrate ions in water.The detection limit of HPO₄^2-and PO₄^3-based on compound 2were 0.375μM and 0.307μM,respectively.（3）Tunable emission colors of bimetallic lanthanide coordination polymers for visualization of latent fingerprints.A series of bimetallic lanthanide coordination polymers[Eu_2xTb_2（1-x）（TDC）₃（phen）₂（H₂O）₂]（x=1,0,0.05,0.2,0.3,0.8,1.6;compound 4-10）were prepared with 2,5-thiophenedicarboxylic acid as main ligand and 1,10-phenanthroline as auxiliary ligand by solvothermal method.The emission colors of the lanthanide coordination polymers could be well tuned by changing the doping ration of the europium（Ⅲ）ion in the host terbium（Ⅲ）-based lanthanide coordination polymers and series of bimetallic lanthanide metal-organic frameworks with different emission colors were obtained.Investigation of visualization of latent fingerprints on various substrates based on these bimetallic lanthanide metal-organic coordination polymers proved that these bimetallic lanthanide metal-organic frameworks were effective enough to visualize latent fingerprints,which indicated a great potential applications in the future.