| Metal-Organic Frameworks materials(MOFs)are a new type of self-assembled inorganic-organic hybrid microporous materials,which have attracted great attention in the fields of gas storage and separation,drug delivery,optical applications,chemical sensing,proton conduction,heterogeneous catalysis research and so on,and have potential and advantages.With the development of society,pollutants such as harmful metal cations,anions,antibiotics and pesticides are a part of the main pollutants discharged from life,agriculture and pharmaceutical industries.Excessive use can cause significant damage to humans and other species.It has become a hot topic to study the efficient,sensitive and rapid detection methods for these pollutants.In this paper,from the perspective of fluorescence detection method,the fluorescence sensing performance of fluorescent metal-organic frame materials for inorganic ions,antibiotics and pesticides is studied.In this paper,we mainly synthesized a carboxylic ligand 4,4'-(1,4-phenylene)bis(methylene oxy)dibenzoic acid(H2PMBB)and a nitrogenous ligand 3,5-bis(1,2,4-triazol-1-yl)pyridine(DTP),and synthesized nine new structural fluorescent metal organic framework materials under solvothermal method by coupling with lanthanide metal salts and transition metal salts.These materials were characterized and characterized by single crystal X-ray diffraction,thermogravimetric analysis,infrared spectrum,elemental analysis,powder X-ray diffraction,fluorescence spectrum and other methods,and then the fluorescence sensing performance of these materials for inorganic ions,antibiotics,pesticides and amino acid was explored.The main research contents are as follows:1.Two new structural complexes Eu-MOF and Tb-MOF,namely[Eu(PMBB)1.5(H2O)2](Eu-MOF)and[Tb(PMBB)1.5(H2O)2](Tb-MOF),were synthesized by H2PMBB ligand with Eu3+and Tb3+.Fluorescence experiments show that Eu-MOF has high sensitivity to Fe3+,Cr2O72-,antibiotics cefixime(CFX),nitrofurazone(NFZ)and pesticides imidacloprid(IMI)and nitenpyram(NTP).Tb-MOF has high sensitivity to Fe3+,Cr2O72-,Mn O4-,antibiotics cefixime(CFX)and pesticides imidacloprid(IMI),so it can be used as a fluorescence sensor.2.Two new structural complexes Zn-1 and Zn-2 have been synthesized by conjugation of DTP ligand with two carboxylic acid ligands 1,3,5-benzenetricarboxylic acid(BTC)and1,4-naphthalenedicarboxylic acid(NTD)with Zn2+,namely[Zn3(BTC)2(DTP)4(H2O)2]·(H2O)4(Zn-1)and[Zn2(NTD)2(DTP)](Zn-2),Zn-1 as a two-dimensional structure and Zn-2 as a three-dimensional structure,all with good water stability.After the fluorescence sensing experiments,Zn-1 was proved to be highly sensitive to Fe3+,Cr2O72-,Mn O4-and antibiotics cefixime(CFX)and the pesticide imidacloprid(IMI).Zn-2 shows high sensitivity to Fe3+,Cr2O72-,Mn O4-and the antibiotic nitrofurantoin(NFT)and the pesticide imidacloprid(IMI),which can be used as fluorescent sensors.3.Two new structural complexes CP-1 and CP-2,namely[Zn(PTA)(DTP)(H2O)2]·(DMF)(CP-1)(DMF=N,N-Dimethylacetamide)and[Zn(BTC)(DTP)]·(CH3CN)1.5·(H2O)4(CP-2),were synthesized based on the combination of DTP ligand with two carboxylic acid ligands terephthalic acid(PTA)and BTC with Zn2+,CP-1 was a chain like one-dimensional structure and CP-2 was a two-dimensional structure,all with good aqueous stability.Fluorescence sensing experiments show that CP-1 is highly sensitive to Fe3+,Cr2O72-and the pesticide metamitron(MMT).CP-2 exhibited high sensitivity to Fe3+,Cr2O72-and the pesticide imidacloprid(IMI),and could be used as a fluorescent sensor.4.Two new structural complexes,Cd-1 and Cd-2,namely[Cd(NIP)2(DTP)(H2O)2]·H2O(Cd-1),were synthesized based on the combination of the DTP ligand with two carboxylic acid ligands,5-nitroisophthalic acid(NIP)and[Cd(NTP)2(DTP)(Et)(H2O)2]·(H2O)0.5(Cd-2)(Et=ethanol),and both materials were two-dimensional structures with good aqueous stability.Through fluorescence sensing experiments,Cd-1 and Cd-2 exhibited high sensitivity(?ex=250/290 nm)for Fe3+,Cr2O72-and good sensitivity(?ex=250 nm)for the pesticides nitenpyram(NTP)and metamitron(MMT)(?ex=290 nm),which can be used as efficient fluorescent sensors.5.A new structural complex Cd-78,namely[Cd(AMP)(DIP)0.5(H2O)]·(H2O)2,was synthesized based on the combination of the DTP ligand with one carboxylic acid ligand 5-aminoisophthalic acid(AMP)with Cd(II)ion,and the material was two-dimensional in structure.Cd-78 against the pesticide dipterex(DIP)by fluorescence sensing experiments(?ex=225 nm),the pesticide imidacloprid(IMI)(?ex=250 nm)and the pesticide metamitron(MMT(?ex=315 nm)with high sensitivity for the acidic amino acid Glu(?ex=225/250/315 nm)have high sensitivity and can be used as fluorescent sensors.It was further investigated that the fluorescence quenching of materials by ions,antibiotics and pesticide contaminants was mainly caused by the mechanisms such as the inner filter effect(IFE)and fluorescence resonance energy transfer(FRET),and there was also a possibility for acidic pesticides and acidic amino acids to change the structure of Cd-78 due to the pH change,which caused the fluorescence change. |
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