Synthesis, Structures, And Properties Of Metal-Organic Framework Materials Based On Bifunctional Ligands With Nitrogen And Carboxylic Acid

Metal-organic frameworks（MOFs） as a branch of porous materials, have attactedmuch attentions because of unique flexible tailoring, various topologies andpromising applications in the area of gas sorption, separation, photoluminescence,catalysts and magnetism.The synthesis condition of MOFs is very mild, and themethod is simple; By selecting suitable biulding blocks and organic ligands to realizethe control of pore shape and dimension. And at the same time, Metal OrganicFrameworks can be endowed with multiple functionalities by choosing functionalmetal ions and organic ligands with functional groups. At present, thousands of MOFshave been reported, nevertheless, targeted synthesis of MOF materials with designedstructures and properties is still a formidable challenge.Based on the principle of crystal engineering, to start from the properties of MOFs,we focus our study on the synthesis, structures and multifunctional properties ofMOFs with various topologies. The purpose of the synthesis is to explore the effectsof structure feathers and properties on the resulting MOFs, such asmetal ions, thedimension and configuration of ligands, solvents, metal-to-ligand ratios and etc. Inthis disertation, we have chosen different organic ligands and constructed11MOFs.The corresponding structure and properties have been studied. These results will beintroduced from the following aspects:1. Four metal-organic frameworks,[Cd₃K（L₁）₆（H₂O）₃]（OH）（DMF）₄（1）[Cd（L₂）₂]（DMF）（H₂O）0.25（2）,[Cd（L₁）₂]（DMF）_0.5（3）,[Zn（L₁）₂]（DMF）_0.5（4）have beensynthesized by using two ligands with different length, configuration, and thecorresponding structures and propeties have been studied. Compound1showsnanosize channel which is constructed by interlocked six-fold one-dimensional helicalchains with the asymmetrical ligand. The hexagonal tubes extend infinitly from adjacent K atoms to construct a3D framework with acs topology. Compound2showsa diamondoid topology with4-fold interpenetration, and displays left andright-handed helical chains in the structure. Compound3is a3D framework with bcutopology. Compound4is a （4,4） layer structure, and further extend to3Dsupermolecular structure with hydrogen bonds. In the end, we discussed the influenceof the chosen ligands to the resulting structures.2. Four metal-organic frameworks,[Cd（L₃）₂]（H₂O）（DMF）_0.5（5）,[Mn（L₃）₂]（H₂O）_1.5（DMF）_0.5（6）, Zn（L4）₂（H₂O）（7）, Cd（L4）₂（H₂O）₂（8）, have beenconstructed by using two ligands with different configurations, and we focus on thestudy of the structures and properties of compound5,6. Compound5is a3D neutralframework possesses a permanent porosity, and displays the selectivity of CO2,compound6shows dominant antiferromagnetic couplings in the structure. And thephotoluminescence of the four compounds have also been studied.3. A two-dimentinal metal-organic framework [Co₂（L₅）Cl（DMF）₂]（DMF）₃（9） basedon the nanometresized ligand has been synthesized and displays the topology of hbc,the magnetic characterization shows that there is ferromagnetic exchange interactionsin the structure; HDMF₂[Cd5（L6）4（H₂O）]（H₂O）₂（CH₃CH₂OH）（10） is a （3,3,12）-c netframework with solvent fluorescence sensing effect.4. Two MOFs Cd（L7）₂（H₂O）（11）, Cd（L8）（H₂O）（12） have been sythesized with theligands4’-（4-carboxyphenyl）-2,2’:6’,2’’-terpyridine（HL₇）,2,2’-bipy-5,5’-carboxylicacid（H₂L₈）. Compound11is a two-fold2D metal-organic framework, and furtherextend to3D supermolecular structures through π-π interaction. Compound12is a3Dmetal-organic framework with1D channels. The photoluminescence has also beencarried out.In summary, we have synthesized several Metal-Organic Frameworks throughsolvothermal method. And studied their properties in the area of gas sorption,photoluminescence, megnetism and etc. We believe that these results would facilitatethe exploration of new MOFs with charming topologies and multifunctionalproperties for directing the synthesis of novel architectures.