Semi-rigid Polycarboxylic Containing Coordination Polymers Design,Synthesis And Properties

In this work,a series of semi-rigid polycarboxylic acid ligands and nitrogen-containing ligands were employed as main and auxiliary ligands reacted with different transition metal to afford 9 kinds of coordination polymers under hydrothermal conditions.The structure,purity and thermal stability of the complexes were characterized by Single-crystal X-ray diffraction,powder diffraction,infrared spectroscopy,ultraviolet spectroscopy,elemental analysis and thermogravimetric analysis.Moreover,the magnetic,fluorescent,electrochemical and organic dye adsorption properties of these complexes were also studied.There are two parts in this work:1.Three complexes,[Co₃（L）₂（dpe）₄（H₂O）₂]_n（1）,{[Co₃（L）₂（dpe）₄（H₂O）₂]（DMF）（2H₂O）}_n（2）,[Co₂（HL）₂（4,4’-bipy）₂（H₂O）₆]_n（3）,were synthesized by using semi-rigid tricarboxylic ligands 4-（（1-carboxynaphthalen-2-yl）oxy）phthalic acid（H₃L）,auxiliary ligands 1,2-di（pyridin-4-yl）ethane（dpe）and 4,4’-bipyridine（4,4’-bipy）,and Co（OAc）₂·4H₂O under solvothermal conditions.Among them,complexes 1 and 2 were obtained by adjusting the ratio of metal to ligand under the same reaction conditions with the same ligand and metal salt.All of the complexes have exhibited a 3D framework with different configurations.In the following electrochemical test of complex 1-3,the reversible redox peak can be attributed to the redox of Co（III）/Co（II）and because of the peak current is proportional to the scan rate,it can be concluded that the redox process is surface controlled.The variable temperature magnetic susceptibility measurement of complex 2 has revealed the existance of weak antiferromagnetic interaction between the Co（II）ions.Organic dyes adsorption experiments show that complex 3 can selectively adsorb methyl orange.2.Three semi-rigid dicarboxylic acid ligands 2-（（4-carboxybenzyl）oxy）-1-naphthoic acid（H₂L₁）,3-（（4-carboxybenzyl）oxy）-2-naphthoicacid（H₂L₂）and1-（（4-carboxybenzyl）oxy）-2-naphthoic acid（H₂L₃）were used to synthesize complex 4-9:[Co₄（L₁）₄（bimb）₄]_n（4）,[Co（L₁）（dpp）]_n（5）,[Co（L₁）（dib）]_n（6）,[Ni（L₁）₂（bimb）₂（H₂O）]_n（7）,[Cd（L₁）（2,2’-bipy）]_n（8）,[Co（L₂）（opi）（H₂O）]_n（9）.The complexes 4 and 8 form a 3D structure through intermolecular hydrogen bonding andπ···πstacking,while the complexes 5,6 and 7 all constructed 3D frameworks by stacking effect.The complex 9shows a three-dimensional interpenetrating structure.The organic dyes adsorption experiments on complexes 4,5,6 and 9 have shown that the adsorption ability is highly related to the electrostatic interaction,the complex’s structure and the structure of the dye molecules.Electrochemical studies of complexes 4,5,6 and 9 indicated that complex 4can be used as a potential electrode material.The complex 8 shows luminescent properties can be used as a potential chemosensor to selectively detect Fe³⁺,Cr₂O₇^2-ion and nitrobenzene.