| A coordination polymer is a one-,two-or three-dimensional coordination compound with periodic structure formed by self-assembly of two different building blocks:metal ions（nodes）and organic ligands（spacers）.By introducing a multi-functional structural unit,the material combines the advantages of organic and inorganic materials,and is widely used in proton conduction,gas adsorption and separation,optics,magnetism,electrochemistry,catalyst and other fields.In this paper,oxalate was used as a bridge ligand to form protonation 4-Methylpyridin-2-amine,N,N’-bis（3-aminopropyl）ethylenediamine,cyclopentylamine,diethylaminopropylamine and 5,5-dimethyl-3,4,5,6-tetrahydropyrimidin-1-ium,3,3’-（ethane-1,2-diyl）bis（3,4,5,6-tetrahydropyrimidin-1-ium）organic cations and 2,3,4,6,7,9,10,11-Octahydro-pyrazino[1,2-a:4,3-a’]dipyrimidine as templates,eight oxalate complexes were synthesized.The structures of eight oxalic acid coordination polymers were analyzed,and the properties of electron conduction and structural phase transformation of these complexes,as well as the OER catalytic performance of three electrocatalysts derived from two structures were studied.Specific work is as follows:（Ⅰ）Two novel oxalic acid complexes{[C5H9NH3]2[Co（C2O4）2]·H2O}n（1）,{[（CH3CH2）NH（CH2）3NH2][Co（C2O4）2]}n（2）,were synthesized using protonated cyclopentamine and diethylaminopropylamine as templates.1 and 2 are one-dimensional chain structure,and the cation is located around the one-dimensional chain.DSC and dielectric tests on 1 show that there is an obvious structural phase transition and dielectric anomaly at 394 K.1 and 2 for the variable temperature conductivity test,temperature of 40℃,the electrical conductivity of 1 to 1×10-11 S/m,when temperature is 100℃,the electrical conductivity of 1 to 1.6×10-10 S/m,temperature of 40℃,the electrical conductivity of 2 to 6.126×10-12 S/m,when temperature is 100℃,The electrical conductivity of 2 to 1.56×10-10 S/m.Two kinds of electrocatalysts composed of flake grains and nickel foam were synthesized by solvothermal method by loading 1and 2 onto nickel foam.Co-C5H11N/NF were further doped with Fe to synthesize FeCo-C5H11N/NF electrocatalysts,the OER-related properties of the three electrocatalysts were tested.The results show that FeOOH and CoOOH nanosheet arrays are formed by surface reconstruction of the three electrocatalysts at high potential.Co-C5H11N/NF,Co-DEAPA/NF needs 290 m V and 330 m V overpotential to reach the current density of 100 m A cm-2,respectively,FeCo-C5H11N/NF had the best properties,reaching the current density of 100 m A cm-2 and only 255m V overpotential,By introducing Fe,we found that the size and morphology of the nanosheets grown on nickel foam were changed to some extent.In addition,the heterojunction of FeOOH and CoOOH is produced,and the adjustment of the electronic structure of the heterojunction makes FeCo-C5H11N/NF have better OER electrocatalytic performance.（Ⅱ）Using solvothermal method,oxalate was used as a bridge ligand to form protonation 4-Methylpyridin-2-amine,N,N’-（ethane-1,2-diyl）bis-（propane-1,3-diamine）and 2,2-dimethyl-1,3-propylenediamine,N,N’-（ethane-1,2-diyl）bis-（propane-1,3-diamine）are cyclized with oxalic acid to generate 5,5-dimethyl-3,4,5,6-tetrahydropyrimidin-1-ium,3,3’-（ethane-1,2-diyl）bis（3,4,5,6-tetrahydropyrimidin-1-ium）organic cations and 2,3,4,6,7,9,10,11-Octahydro-pyrazino[1,2-a:4,3-a’]dipyrimidine as templates,six oxalate complexes were synthesized:{[DTHPM]2[CO2][Fe2（C2O4）3]}n（3）,{[C6N2H8][Fe（C2O4）Cl2]}n（4）,{[OPDM][Mn（C2O4）]}n（5）,{[NH3（CH2）3NH（CH2）2NH（CH2）3NH3][Fe2（C2O4）3]}n（6）,{[NH3（CH2）3NH2（CH2）2NH2（CH2）3NH]0.5[H2O][Fe2（C2O4）3]}n（7）,{[EDTM][Fe2（C2O4）3][C4O2H8]2}n（8）,through structural analysis,it is found that 3,6 and 8 are two-dimensional layered structures,the cations（DTHPM,EDPM,EDTM）are distributed in two-dimensional layer,6 protonated ammonium organic cations across the two-dimensional layered skeleton.the organic cations（EDTM）in 8 are partially disordered,3 for the variable temperature conductivity test,temperature of 40℃,the electrical conductivity of 3 to1.8×10-10 S/m,when temperature is 90℃,the electrical conductivity of 3 to 4.48×10-9S/m,and 4 and 5 are one-dimensional chain structure.The organic ammonium cation of 4 is partially disordered,and the organic ligand tricyclamidine（OPDM）is chelated with Mn ion in 5,through the variable temperature conductivity test found that temperature of 40℃,the electrical conductivity of 4 to 2.09×10-8S/m,when temperature is 150℃,the electrical conductivity of 4 to 4.31×10-7S/m,7 is the three-dimensional structure,protonated organic ammonium cations（EDPM）are distributed in a three-dimensional framework,conducting tests on the variable temperature,temperature of 30℃,the electrical conductivity of 7 to 2.01×10-8S/m,when temperature is 130℃,the electrical conductivity of 7 to 4.1×10-7S/m. |
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