Synthesis And Properties Of Coordination Polymers Based On Aromatic Or Imidazole Carboxylic Acid Ligands

In recent years, due to their intriguing network topologies and the great potentialpractical applications in many fields, such as catalysis, separation, gas storage, thedesign and synthesis of novel organic-inorganic hybrid polymers have attracted greatattention. As a branch of hybrid system, carboxylate acid coordination polymers arebecoming an ever-increasing interested field, for the versatility of coordination modes,strong bridging ability and high thermal stability. It is a urgent question to design andsynthesize the complexes with specifical structures and properties，and to implementtheir potential application. This dissertation reports the constructions and properties ofseveral complexes incorporating different aromatic carboxylate ligands and imidazolecarboxylate ligands.Two complexes [Ag₄（μ-Hbtc）（μ-H₂btc）]n （1） and [Cd（μ3-Hbtc）（H₂O）（2） basedon the trimesic acid ligand and the Ag（Ⅰ）, Cd（Ⅱ） ion were synthesiedbyhydrothermal method, and their crystal structures of the complexes were characterized.The thermostability and fluorescent properties were investigated furtherly. The resultsshow that complex1exhibits strong emission band at498nm for the Ag……Aginteraction, which is a good fluorescent material.Two new complexes [Cd（H₃imdc）₂（H₂O）₂]（3） and [Cd（μ3-H₃imdc）（Bim）]n （4）based on the imidazole-4,5-dicarboxylic acid were synthesised by hydrothermalmethod and their crystal structures were characterized. Moreover the thermostabilityand fluorescent properties of the complexes were analysed. The results reveal that theemission peaks of complex3and4have a big shift campared with the free ligands forinteraction of the ligand and metal ions （ligand-to-metal charge transition, LMCT）. Asto high thermal stability and strong fluorescence emission, the complex4proves to bea useful photoactive material.[（CH₃）NH₂]₃[（Cu₄Cl）₃（btc）₈]·9DMA （5） membrane was prepared on α-Al₂O₃substrateby the in-situ solvent thermal method, and characterized by ESEM, PXRD. Thepreparing process of the membrane was investiged. Furthermore, fractalcharacteristics were identified from the analyzing results in fractal theory. Meantime,the impact of different conditions on synthesis of complex5membrane wasconsidered, such as time, temperature, the ratio of Cu²⁺/H₃btc and concentration ofreactant. The results show the optimal synthetic conditions of the complex5 membrane is as follows: Cu²⁺/H₃btc=1:1, the reaction temperature is100℃, thereactant concentration is0.067mol/L, the reaction time is48h. Finally, the fractaldimensions of the complex5membrane were determined by the gray scaledistribution of the ESEM images in box-dimension method. The morphology of thecomplex5membrane exhibits self-similarity and the complex membrane have fractalproperties.