| As a new type of organic-inorganic hybrid material,metal-organic frameworks(MOFs)has been applied in many fields such as gas storage and separation,molecular recognition,adsorption of pollutants,due to its advantages of simple synthesis methods,adjustable structure and high specific surface area.In this thesis,three sulfonate-carboxylate organic ligands and different metals were used to construct 12 novel MOFs,and their structures and properties were investigated.Chapter 1:the concept,synthesis methods and the research development of MOFs based on sulfonate-carboxylate organic ligands were introduced.And the application of MOFs in fluorescence detection,adsorption of pollutants,gas storage and separation were studied.Chapter 2:five 3D lanthanide metal-organic frameworks(Ln-MOFs)[Ln(ABS)(H2O)2]n[Ln = Tb(1),Eu(2),Dy(3),Sm(4),Gd(5),H3ABS = 4-(N,N’-bis(3-carbonyl-benzyl)amino)benzenesulfonic acid]have been solvothermally synthesized and fully characterized.Compounds 1-4 exhibit characteristic emission peaks as well as long fluorescence lifetimes.Compound 1 could detect Fe3+ and organic small molecules(salicylaldehyde,pirimicarb)by fluorescence quenching phenomenon,and exhibiting high selectivity and recyclability.Besides,compound 1 could also detect Fe3+ in a simulated physiological condition,indicating it could be regarded as a luminescent sensor in a biological system.mechanisms of the quenching effects have been investigated in detail.The luminescence of compound 1 is generated by ligand-to-metal energy transformation(LMET).The absorption spectra of the analytes and ligand have a large overlap,there exists the competition of absorption of the light source energy between the analytes and ligand H3ABS moieties.The analytes reduce the absorption of excitation energy of ligand,thus decrease the efficiency of ligand-to-metal energy transfer,which leads to fluorescence quenching phenomenon.Chapter 3:five MOFs have been successfully assembled by 2-sulfoterephthalic acid monosodium and bridging ligands with transition metal ions(Co2+,Zn2+,Cd2+):[Zn2(SIP)2(PETPE)]n(compound 6),[Zn(OH)(STP)(bmb)1.5(H2O)]n(compound 7),[Cd3(STP)2(bib)4]n(compound 8),[Co3(STP)2(bib)4]n(compound 9),[Co(HSTP)(bimb)(H2O)]n(compound 10).Compound 6 is an anionic framework and has two kinds of regular channels with dimensions of 3.7 × 3.9 A2 and 8.3 × 9.6 A2 along the a-axis,affording a void space of 52.6%(calculated by PLATON).It could selectively adsorb methylene blue(MB+)and iodine in cyclohexane solution.The total solvent-accessible volumes of compound 7 is calculated to be 25.6%,and the structure contains a one-dimensional channels modified by polar sulfonic acid groups.There exists the strong force between CO2 and sulfonate groups,which make compound 7 exhibit superior adsorption enthalpy for CO2.Chapter 4:[Zn2O(HSIP)(PETPE)]n(compound 11)and[Co3(OH)(SIP)2(H-PETPE)(H2O)3]n(compound 12)have been solvothermally synthesized by 5-sulfoisophthalic acid monosodium and tetrakis(4-pyridyloxy-methylene)methane(PETPE)with transition metal ions(Co2+,Zn2+).Compounds 11 and 12 are porous MOFs,the total solvent-accessible volumes of them are 25.3%and 47.8%,respectively.Compound 11 has a strong adsorption capacity to CO2 and exhibits high selectivity for CO2/CH4 at room temperature.Compound 12 has unsaturated coordination sites and adsorption capacity for CO2,which can be used as a heterogeneous catalyst to catalyze the reaction of CO2 with epoxides for the synthesis of cyclic carbonates.Chapter 5:the research results and innovation points of the thesis were summarized,and prospects of the construction of MOFs with novel structure and versatility was introcduced. |
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