Synthesis And Characterization Of Two Types Of Aromatic Ligands And Their Metal Coordination Polymers

In this paper, the development, classification, synthesis methods, influenced factors andpotential applications on metal coordination polymers were outlined.The core of this paper is composed of two parts: the synthesis and characterization ofthree aromatic ligands; synthesis and characterization of the corresponding series ofcoordination polymers. So we synthesized two types of three organic ligands, thensynthesized eight coordination polymers with different dimensions under hydrothermal orsolvothermal conditions, and through elemental analysis, X-ray single crystal diffraction,powder diffraction, thermogravimetric analysis, fluorescence analysis and other methods, westudied their structures and properties. The specific findings are summarized as follows:1.Synthesis of three organic ligands:1,2,4,5-tetrabromobenzene and4-（methoxycarbonyl）phenyl boronic acid as raw materials, through Suziki coupling,esterification and hydrolysis, we synthesized1,2,4,5-tetra（carboxyphenyl）benzene （ligand L₁）.And we synthesized1,2,4,5-tetra（4-pyridyl）benzene （ligand L₂） and1,2,4,5-（3-pyridyl）benzene （ligand L₃） using1,2,4,5-tetrabromobenzene and pyridine-4-boric acid orpyridine-3-boric acid with Suziki coupling reaction.2. Synthesis of eight coordination Polymers:（a） Under the hydrothermal or solvothermalconditions, coordination polymers [Co2（L1）（H2O）4]n（1） and [Co₂（L1）（DMF）₂（H₂O）]n（2） weresynthesized from ligand L1and transition metal salts Co（OAc）₂4H₂O, Co（NO3）26H2O.（b） Under solvothermal conditions, coordination polymers [Cu₂（L₂）Br₂]n（3） and[Cu2（L₃）（DMSO）Br₂]n（4） were synthesized from ligand L₂/L₃and transition metalCu（NO3）23H2O.（c） Under hydrothermal conditions, L₃as the main ligand and aromaticcarboxylic acids （benzoic acid, phthalic acid, benzene-1,3,5-tricarboxylic acid,benzene-1,2,4,5-tetracarboxylic acid） as the second ligand, they reacted with transition metalsalt CoCl₂6H₂O respectively, then a series of coordination polymers [Co（L₃）（Hbc）₂（H₂O）₂]n（5）,[Co₂（L₃）₃（H₂bdc）₂]n（6）,[Co₂（L₃）₂（H₃btc）₂（H₂O）₄]n（7） and[Co₂（L₃）₂（H₄btc）]n（8） were synthesized.3. Characterization of coordination polymers: The crystal structure of coordinationpolymers were characterized by X-ray single crystal diffraction. The purity of somecoordination polymers were identified by the powder X-ray diffraction spectrums, the resultsshows that they are pure. The thermal stability of all coordination polymers were studies bythermogravimetric analysis （TGA）, the results indicate that they have good thermal stability.Coordination polymer（3） was characterized by fluorescence spectrum, the analytic datashows it has weak luminescent property.