Synthesis And Properties Of Functional Complexes Based On Aromatic Tetracarboxylic Acids

Aromatic tetracarboxylic acid ligands with a rigid structure contain a lot of coordination sites and a variety of coordination modes.The purpose of this paper is to construct metal organic framework complex for use in optical sensing,super capacitors,etc.Two kinds of tetracarboxylic acid ligands with the different substitution sites and the transition metals Zn and Co were successfully assembled by hydrothermal synthesis respectively.Five functional complexes with novel structures were synthesized and characterized.The details are summarized in the following four chapters:In the first part,a brief description of the ingredient and application of MOFs,focusing on its research background and progress in the field of fluorescence sensing,supercapacitors.The significance of the topic and the results obtained are briefly described.In the second chapter,two fluorescent functional complexes have been reported using2,2′,5,5′-triphenyltetracarboxylic acid ligand connected with transition metal Zn through a hydrothermal reaction:[Zn₂（qptc）]（1,2 Bim）·（H₂O）·DMF（1）and[Me₂NH₂][Zn₃（qptc）₂（H₂O）₂]（2）.In the complex 1,the Zn（II）and the qptc^4-ligands are connected into a two-dimensional plane in a fishbone shape,and the two-dimensional layer is further constructed in the vertical direction by the ligand 2-imidazole propane to form a 3D framework structure,free DMF molecules and water molecules filled in the hole.And 1 can selectively detect S₂O₃^2-by fluorescence,giving a great enhancement of fluorescence.As well as it also can remove MnO₄^-in solution,which can be used as a template experiment to remove radioactive TcO₄^-.There are free dimethylamine cations in 2 and can selectively detect Al³⁺in aqueous solution with a detection limit of 4.68μM.2 Detection of Al³⁺shows a strong fluorescence enhancement effect.The third chapter,three novel porous coordination polymers were synthesized by using Co as the metal center ion and two rigid aromatic tetracarboxylic acids:Co₂（tptc）（4.4′-bpy）·（DMF）₂（3）,Co₂（qptc）（4）and Co₂（qptc）[NH（CH₃）₂]₂（5）.We explored the electrochemistry performance of the original 3 and 5,and added PPy with good conductivity to the MOF through in-situ synthesis.We designed a 3-PPy and 5-PPy by adding different ratios of PPy as a super capacitor electrode material which has a higher specific capacitance than the original MOF and has a high capacitance retention rate of 90.7%,99.9%after many cycles.Therefore,it has good electrochemical performance in the three-electrode system of KOH electrolyte.The fourth chapter,a concise conclusion is drawn and a prospect of this research area is anticipated.