Syntheses And Properties Of Hydroxyl And Amino Functionalized Metal-Organic Frameworks

As proved,Metal-Organic Frameworks?MOFs?have been widely used in adsorption-separation,reaction catalysis,luminescence,energy storage,biotechnology and other fields.Compared with pure MOFs,functionalized MOFs have a better prospect of application.The synthetic approachs of functionalized MOFs include pre-modified synthesis and post-modified synthesis.Generally,pre-modified synthesis is to make the ligands have certain functionality through ligand modification.Post-modified synthesis is to modify the pre-synthesized MOFs to show the required functionality.In the first part of the thesis,the amino modified polycarboxyl ligand H₅L¹ and the hydroxyl modified polycarboxyl ligands H₅L² and H₆L³ were designed and synthesized.In order to make the MOFs more functionalized,-NH2 and-OH was introduced.In the second part,the amino-modified polycarboxyl ligand H₅L¹ was employed,and two new MOFs were synthesized by solvothermal method:[?CH₃?₂NH₂⁺][Zn₂?L¹?]·2DMF·H₂O?complex 1?and[Cu₂?HL¹??DMF?₂]·H₂O?complex 2?,which were characterized by single crystal X-ray,TG,IR,PXRD and gas absorption-desorption.The single crystal X-ray analysis shows that the complex 1 has larger pores in the a and c directions,also it is an anionic framework material.Therefore,the adsorption performance of organic dyes of complex 1 was investigated,and it was found that complex 1 had better adsorption of cationic dye MB and certain adsorption of neutral dye CMH6.As the same time,the complex 1 has an uncoordinated amino functional group.Its catalytic application in the Knoevenagel reaction was also studied.The results show that the complex 1 can quickly catalyze the Knoevenagel reaction at room temperature,the conversion rates are all around 99%in 5 cycles.The single crystal X-ray analysis of complex 2 is a neutral skeleton material uncoordinated amino groups and carboxyl groups,alao has larger pores in the c direction.The IR data also proves the existence of uncoordinated amino and carboxyl groups.Complex 2 has good solvent stability and can maintain its crystal form in water for more than 24 h,and in common polar solvents such as ethanol,methanol,acetone,acetonitrile and dichloromethane for more than 48 h.Since complex 2 has acid-base functional groups simultaneously,then we investigated the performance of complex 2 in catalyzing the deacetalization-Knoevenagel reaction.The results show that the complex 2 can effectively catalyze the deacetalization-Knoevenagel reaction in DMF at 90?,and the reaction can be recycled more than 3 times.In the third part of the thesis,the polycarboxyl ligand H₅L² was employed,and two new MOFs was synthesized by solvothermal method:[?CH₃?₂NH₂⁺][Zn₂?L²??H₂O?]·3DMF?complex 3?and Cd₅?L²?₂?H₂O?₇?complex 4?,which characterized by single crystal X-ray,TG,IR,PXRD and gas absorption-desorption.The single crystal X-ray analysis shows that the complex 3 has larger pores in the a and the c directions,and the complex 3 is an anionic framework material.Complex 3has good thermal stability and solvent stability.Solid fluorescence analysis shows that complex 3 has good fluorescence properties,and the change of complex 3fluorescence can be used to specifically detect the trace amounts of Fe³⁺and2,4-dinitroaniline.The complex 4 is a 3D frame material,composed of a four-core Cd-O cluster and a single-core Cd-O cluster.The complex 4 has a larger pore in the c direction.Due to the poor solvent stability,further research hadn't been done yet.