The Synthesis, Proton Conductivity And Fluorescence Properties Of Porous Coordination Polymers Based On Polycarboxylate Ligands

We are surrounded by all kinds of materials,which not only insure our living activities,at the same time,their development have also promoted the whole social progress.Porous polymers（PCPs）or metal-organic frameworks（MOFs）,a new type of pore materials,became research hotspots in the material field relying on unique advantages of structure and property characteristics.After a long time and extensive studies,it has been found that PCPs/MOFs are widely used in all aspects of human life.For example,PCPs/MOFs can be used as proton conducting materials for fuel cells,gas adsorption materials for energy gas storage,drugs transport materials in the field of medicine,etc.Over the past decade or so,the research and development of such materials have been overwhelming,making thousands of PCPs/MOFs with different structures have been reported currently.Obviously,it is no longer important to continue to study the structure of these materials.Therefore,considering the application of PCPs/MOFs in practical production and life,it is necessary to study the relationship between its synthesis and structure or performance,in order to achieve directional design and synthesis PCPs/MOFs material with specific functions.In this dissertation,we selected two kinds of multi-carboxylic ligands and one kind of N-heterocyclic organic ligand as organic linker connecting d10 metal ions constructing six novel PCPs/MOFs materials and investigation their properties in acid-base stability,solid-state fluorescence and proton conductivity.The details are as follows:（一）We used the diffusion method to construct a new type of three-dimensional PCPs（PCP1）（一）We used the diffusion method to construct a new type of three-dimensional PCPs（PCP1）using tpy as N-heterocyclic organic ligand and Cd ions under hydrothermal conditions.In this structure,there is a one-dimensional open channel along the c-axis direction,and there are a large number of guest water molecules in the channel.For this feature,we experiment on the proton conduction of PCP1.The conductivity was 1.81 × 10-5 Scm-1under 97% relative humidity and 95 ℃ condition.The experimental results show that PCP1 has capability of proton conductivity in the high humidity environment.In addition,the crystal structure of PCP1 began to collapse at 410 ℃,and PCP1 exhibits excellent chemical stability under various organic solvents and aqueous solution with different p H values ranging from 2 to 13,the above shows that PCP1 possesses good thermal stability and chemical stability.[Cd_0.5（tpy）] ·0.75H₂O （PCP1）tpy=2-（1H-1,2,4-Triazol-5-yl）pyrazine（二）We used Nitrogen-containing multi-carboxylic organic ligands（tda）with Cd ions,and selected 2,2′-bipyridine,1,10-phenanthroline as co-ligands,respectively,to construct two novel MOFs materials（MOF1,MOF2）under solvothermal conditions.Both of them are three-dimensional coordination polymer materials formed by one-dimensional chain structures linked by multiple π-π stacking.The experimental results show that MOF1 and MOF2 can maintain good stability in the range of p H=2-12 and common organic solvents,which shows that the two MOFs have good chemical stability.In addition,as their thermogravimetric analyses showed,the two isomeric compounds had a small difference in the thermal stability temperature,and it was found that this is derived from the π-π stacking generated between the second ligands.Cd（tda）（2,2’-Dipy） （MOF1）Cd（tda）（1,10-phen） （MOF2）tda=3,3’-（1H-1,2,4-triazole-3,5-diyl）dibenzoic acid2,2’-Dipy=2,2’-Dipyridyl1,10-phen=1,10-Phenanthroline monohydrate（三）We successfully synthesized three novel MOFs（MOF3,MOF4 and MOF5）by using multi-carboxylate ligands with threefold symmetries（tcpb）with zinc,cobalt and cadmium ions through solvothermal method.In which MOF5 is a three-dimensional MOFs material with triple interpenetrating framework.Meanwhile,the other two（MOF3 and MOF4）are two-dimensional layers structures.In addition,MOF3 and MOF4 are isomorphic structures.We have carried out solid fluorescence tests on these three MOFs and found that the maximum emission peak of the three MOFs showed a larger redshift compared with that of pure organic ligands.[Cd_1.5（tcpb）（DMF）（H₂O）]（MOF3）Co_1.5（tcpb）（DMF）₂]·3DMF（MOF4）[Zn（Htcpb）（4,4’-bpy）_0.5]·1.5H₂O（MOF5）tcpb=1,3,5-tris（4-carbonylphenyloxy）benzene4,4’-bpy=4,4’-Dipyridyl...