| Metal-organic framework compounds(MOFs)have the advantages of porosity,high specific surface area,and tunable structures.In recent years,it has shown great application prospects in the fields of adsorption,fluorescence,magnetism,catalysis and drug delivery.Ionothermal synthesis is a new method for the preparation of MOFs.In the process of materials synthesis,ionic liquids play various vital roles,such as reaction media,structural templates and charge balancer.The structures and properties of the obtained MOFs can be regulated by changing the composing cations and anions of ionic liquids.In this paper,[PMI]Br(1-propyl-3-methyl imidazolium bromide)and[BMI]Br(1-butyl-3-methyl imidazolium bromide)were used as the main reaction media for the ionothermal synthesis of five different metal organic complexes.Zn(NO3)2·6H2O,and Cd(NO3)2·4H2O were employed as the metal ion sources,while H3BPT(biphenyl-3,4?,5-tricarboxylic acid),H3TPT(3,5-bis(4-carboxyphenyl)benzoic acid),H3BTB(1,3,5-tris(4-carboxyphenyl)benzene),BPY(4,4?-bipyridine)were selected as organic bridging ligands.Three Zinc MOFs(1-3)and two Cadmium MOFs(4 and 5)were obtained by changing the combination of ligands and metal salts.The structures and properties of the five complexes were studied by single crystal X-ray diffraction,powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA),infrared spectroscopy(IR)and fluorescence spectroscopy.In addition,the luminescence sensing and dye adsorption properties of these compounds were investigated.The main results of the study are summarized as follows:The three Zinc MOF compounds reported in Chapter 2 are all three-dimensional(3D)frameworks with corresponding formula as[PMI]2[Zn4(?4-O)Br2(BPT)2](1),[BMI][Zn2(BTB)Br2](2)and[BMI]2[Zn3(BTB)2(BPY)Br2](3).The two Cadmium MOF compounds reported in Chapter 3 can be divided into two types according to their crystal structures:[BMI]4[Cd3(TPT)2(OH)2Br2](4)possesses a 3D framework,while[BMI]3[Cd3(BTB)2(NO3)Br2](5)contains a 2D layered structure([PMI]=1-propyl-3-methylimidazolium cation,[BMI]=1-butyl-3-methylimidazolium cation).Because of the use of bromide-containg ionic liquids,Br-ions binding to the metal centers exist in the secondary building units(SBUs)of all five complexes.Reports on MOFs with halogen-containing SBUs are relatively rare in the literature,hence,ionothermal synthesis has provided a new strategy for the introduction of halogen into MOF structure motifs.In addition,ionic liquid cations are included in the structures of these complexes,indicating that ionic liquid cations act as templates in the formation of MOF frameworks.Also,due to the presence of these imidazolium cations,the resulting frameworks are anionic.This demonstrates the synergistic effect of imidazolium cations and halide anions on the introduction of halogens and formation of charged frameworks.In terms of fluorescence performance,1 and 5 can specifically detect Fe3+in DMF,and 3 can detect fluorescence of Fe3+in water,so 1,3 and 5 can be used as quenching fluorescent probes for Fe3+.In addition,2 and 3 can be used as quenching fluorescent probes to detect MnO4-?Cr2O7(17)-and CrO4(17)-anions in water by selective fluorescence recognition.The results of the study on the nitro compound show that the compounds2 and 5 can specifically detect the nitro compound containing a benzene ring and have a good quenching effect.As for dye adsorption,compounds 1-5 are anionic framework compounds,so they can selectively adsorb cationic dyes such as malachite green,methylene blue and rhodamine B.Compounds 2 and 3 can also adsorb anionic dyes,I.E.congo red.The adsorption experiments of organic dyes confirmed the possibility of the application of the series of samples in selective adsorption and purification of dyes and industrial wastewater treatment. |
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