Structures And Properties Of Metal-Organic Frameworks Constructed From 5-(4-pyridyl)-methoxyl Isophthalic Acid

Coordination polymers or metal-organic frameworks(MOFs)have attracted great attention due to the possibility to obtain a large variety of aesthetically interesting structures that could also be of great interest for application in many fields such as gas storage,luninescence,catalysis,biomedicial and so on.In this thesis,we have synthesized 10 new MOFs based on 5-(4-pyridyl)-methoxyl isophthalic acid(5,4-PMIA)and four kinds of neutral bridging ligands,structures and properties of MOFs were also studied detailedly.Chapter 1:the concept and synthesis methods of MOFs were conceemed.Meanwhile,the research progress of MOFs based on pyridine carboxylic acid were introduced sententiously,especially about 5-(4-pyridyl)-methoxyl isophthalic acid.In addition,there were multiple potential applications of MOFs were presented in gas adsorption and separation,luminescence,dye adsorption and separation,as well as iodine adsorption.Chapter 2:three new MOFs based on 5-(4-pyridyl)-methoxyl isophthalic acid and pentaerythrityl-tetrakis(4-pyridyl)ether have been solvothermally synthesized and characterized.They are[Ni2(5,4-PMIA)2(PETPE)0.5]n(1),[Co2(5,4-PMIA)2(PETPE)0.5]n(2)and[Cu(5.4-PMIA)]n(3)respectively.Compound 1 and Compound 2 are isostructural,the solvent accessible volume per unit cell for 1 is calculated to be ca.43%by PLATON program,compound 2 is ca.45%.Compound 1 and 2 show preferable thermal and chemical stability,they could absorb gas small molecules,such as CO2?H2?C2H2?C2H4?C2H6.Ideal adsorbed solution theory(IAST)of compound 2 exhibit good CH4 separation capability toward C2 hydrocarbons at room temperature.It's remarkable that compound 1 could be used as adsorbent for small molecule dyes and the adsorption behavior was highly size-dependent for organic dyes.In general,on the premise that the dye molecular sizes are smaller than the diameter of channel for compound 1,the adsorption processes become slower with the size of the dyes increasing.In addition,compound 1 also could absorb iodine in cyclohexane solution by the host-guest interaction.Chapter 3:two new MOFs[Cu(5,4-PMIA)(tib)]n(4)and[Cd(5,4-PMIAXtib)]n(5)were solvothermally synthesized with 5-(4-pyridyl)-ethoxyl isophthalic acid and 1,3,5-tris(1-imidazolyl)benzene.The solvent accessible volume per unit cell for 4 is calculated to be ca.28%by PLATON program.Compound 4 exhibits rapid uptake and regeneration for the methyl orange in aqueous solution.Owing to the pore size of compound 4 is between the dimensions of methyl orange and methylene blue,only methyl orange is likely to enter the channel,so it could selectively adsorb methyl orange from the mixed aqueous solution.In addition,compound 4 also could absorb iodine in cyclohexane solution by the host-guest interaction.Chapter 4:we have synthesized one Luminescent MOF:[Zn2(5,4-PMIA)2(bimb)]n(6),which were constructed by 5-(4-pyridyl)-methoxyl isophthalic acid and 4,4'-bis(1-imidazolyl)-biphenyl.The fluorescence spectra of compound 6 indicated that it could sensitively identify and detect I-and AFB1 in DMA.Moreover,compound 6 could sensitively detect I-in the presence of interfering ions.The absorption spectra of AFB1 and emission spectra of MOF have a partial overlap,which led to energy transfer from compound 6 to AFB1,thus causing fluorescent quenching.Chapter 5:four MOFs,[Cd(5,4-PMIA)(bib)0.5]n(7),[Zn2(5,4-PMIA)2(bib)]n(8),[Ni2(5,4-PNEA)2(bib)]n(9),[Cu(5,4-PMIA)(bib)0.5]n(10)were constructed by 5-(4-pyridyl)-ethoxyl isophthalic acid and 1,3-bis(imidazol-1-ylmethyl)benzene.Compound 7 and 10 are isostructural,Compound 8 and 9 are isostructural.More interesting,these MOFs have the same topology type.The fluorescence spectra of compound 7 indicated that it could sensitively identify and detect two different types of analytes(Fe3+,salicylaldenyde).Moreover,compound 7 could sensitively detect Fe3+,salicylaldehyde in the presence of interfering substance.Compound 7 could also detect Fe3+ in a simulated physiological condition,indicating it could be regarded as a luminescent sensor in a biological system.Chapter 6:the research findings and innovation of this thesis were summarized,as well as the prospects for structure and function of the MOFs.