Design,Synthesis And Properties Of Coordination Polymers Containing Rigid Polycarboxylic Acids

In this paper,three rigid carboxylic acid ligands and metal cations(Ni²⁺,Co²⁺,Zn²⁺)were selected to obtain six complexes by the solvothermal method.Some conventional characterizations were carried out,such as:infrared spectroscopy（FTIR）,X-ray Single crystal diffractometer（APEX CCD）,thermogravimetric analysis（TGA）,X-ray diffraction（XRD）and scanning electron microscopy（SEM）.A series of studies have been conducted on the related properties of complexes by these characterizations.1.Nitrogen-containingrigidcarboxylicacidligand3,5-bis（3’,5’-dicarboxylphenyl）-1H-1,2,4-triazolec（H₄L₁）,transitionmetal salts·Ni（NO₃）₃·6H₂O and NiCI₂·6H₂O were selected to synthesize two different complexes by hydrothermal method.Complex 1 has a 3D structure,which processes a（46·52·62）-connected topology,where the distance of the node is216.5082/12.1485/9.7532.Complex 2 formed a six-coordinated twisted octahedral structure,and the 2D layer formed a three-dimensional supramolecular structure by hydrogen bond.Besides,complex 1 has a pair of redox peaks in the cyclic voltammetry scan due to the mutual conversion of Ni（II）/Ni（III）.In addition,the two complexes are calcined to form oxides,and then the properties of the four materials on the supercapacitor are studied.Finally,it was concluded that the excellent electrochemical properties of Ni-MOF-derived NiO were attributed to increase in surface area and structural stability.2.Using two asymmetric rigid carboxylic acid ligands,3,5-bis（3’,5’-dicarboxylphenyl）-1H-1,2,4-triazole（H₄L₁）and 5-（3’,5’-dicarboxylphenyl）nicotinic acid)（H₃L₂）reacted with Co（NO₃）₃·6H₂O and obtained three novel complexes.Comparing the properties of the oxide of calcination on the supercapacitor complex 3 and the complex 5 after calcination on the supercapacitor,it can be seen that the capacitance performance of the oxide after calcination is improved.Futhermore,the photocatalytic degradation of dyes by three complexes was studied.It can be found that the degradation and the size of the dye have a certain relationship.Finally,it was found that the structure of the complex 4 was not changed after immersion in different solvents,which proved that it has good stability.3.The complex 6 was synthesized by hydrothermal method using3-（3’,5’-dicarboxyphenyl）pyridine-2,6-dicarboxylic acid（H₄L₃）and Zn（NO₃）₃·6H₂O.The asymmetric unit of complex 6 consisted of an independent Zn（II）Atom,an unprotonated H₂L₂^-anionic ligand and a coordinated H₂O molecule.The quenching phenomenon of the detection of nitrobenzene（NB）by complex 6 was mainly studied.The mechanism of detection was the interaction between the guest molecule and the coordination framework,such asπ···πinteraction and hydrogen bond interaction,and then has good reusability in the detection process.