Synthesis And Sensing Properties Of Multifunctional Luminescent Metal-organic Frameworks

LMOFs,as organic and inorganic hybrid materials,integrate the advantages of organic and metal luminescent materials,which have tunable channel structure,good stability,excellent luminescent properties and functional reaction sites.Therefore,LMOFs can be used as both fluorescent probes to detect pollutants in the environment and white light emission materials.(1)2,5-bis-(3,4-dicarboxyphenyl)thiophenediformamide is designed and synthesized,a case of Cd-MOF is synthesized by using it as an organic ligand and the transition metal Cd2+ion.Cd-MOF has been used to analyze and characterize it by various means.X-ray single crystal diffraction results show that Cd-MOF has a novel three-dimensional skeleton structure.(2)Based on the principle of three primary colors,a series of rare earth MOFs were synthesized by using 4,4'-(4,4'-bipyridine-2,6-diyl)dibenzoic acid(H2bpydb)as ligand and rare earth metal ions:EuxTb1-x-MOF(x=1,0.005,0.00667,0.01,0.02,0),EuxTbySm1-x-y-MOF?EuxTbyNd1-x-y-MOF?EuxTbyYb1-x-y-MOF(x=0.0476,y=0.8571;x=0.0323,y=0.9032;x=0.0244,y=0.9268;x=0.0196,y=0.9412;x=0.0099,y=0.9703;x=0.0066,y=0.9801;x=0.0050,y=0.9851).The luminescence properties of double rare earth MOFs and tri-rare earth MOFs were studied by adjusting the content and excitation wavelength of rare earth ions.The results show that Eu0.01Tb0.99-MOF?Eu0.0196Tb0.9412SM0.0392-MOF?Eu0.0196Tb0.9412Nd0.0392-MOF?Eu0.0244Tb0.9268Yb0.0488-MOF are nearly white light emitting materials.(3)The fluorescence sensing performance of Cd-MOF for contaminant ions and small organic molecules in the environment is discussed.The experimental results showed that Cd-MOF,as a fluorescent sensing probe,have obvious fluorescence quenching effect on Fe(?)?Cr(?)and nitroaromatic compounds.In addition,Cd-MOF has a stable structure in acid-base solutions with pH=4-10,and can also be used as a sensitive pH sensor material to monitor small changes in pH=3-4.The sensing properties of Eu-MOF,Tb-MOF and Eu0.01Tb0.99-MOF materials are discussed.The results show that they all have good detection effect for p-nitroaniline,p-nitrophenol and o-nitrophenol.In conclusion,Cd-MOF?Eu-MOF?Tb-MOF?Eu0.01Tb0.99-MOF materials as fluorescent probes have a feasible development prospect in the detection of environmental pollutants.