The Syntheses,structures And Properties Of The Coordination Polymers Based On Nitrogen-containing Polydentate Ligands

Metal-organic coordination polymers are a kind of organic-inorganic hybrid material,which are mainly formed by self-assembly of metal and organic ligands.Due to the introduction of functional organic ligands and metal ions,coordination polymers not only possess the activity of metal ions,but also obtain the flexibility of organic ligands,the selectivity of functional groups and the special space structure formed by coordination.Therefore,MOFs have structural diversity and potential applications in many fields.The introduction of different organic ligands plays an important role in the structure and performance control of MOFs.In this study,two flexible nitrogen-containing polydentate ligands were synthesized:tris(4-(1H-imidazol-1-yl)phenyl)amine(Tipa),tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine(Ttpa).Three aromatic carboxylic acids(5-nitro-1,2,3-benzoic acid(H3nbta),5-nitroisophthalic acid(NO2-H2BDC),o-nitrobenzoic acid(ONBA)and transition metal of Co(?),Cu(?),Cd(?)and Zn(?)were selected.By adjusting reaction temperature,solvent and pH value of solvent,eight metal-organic coordination polymers were synthesized including[Co(Tipa)(COO)2(H2O)]·H2O(1)?[Cu(Tipa)(OH)2]-2H2O(2)?[Cd(Tipa)(COO)2]2·H2O(3)?[Cd(Tipa)(NO2-BDC)]·H2O(4)?[Cd(Tipa)(ONBA)2]-4H2O(5)?[Cu(Ttpa)(NO2-BDC)]·H2O(6)?[Cu(Ttpa)(ONBA)(COO)]·4H2O(7)?[Zn(Ttpa)(NO2-BDC)(H2O)]2·H2O(8).The structure of the compound were characterized by X-ray single crystal diffraction and infrared spectroscopy.The properties of the compound were studied by thermogravimetric analysis?Supercapacitor performance and dye degradation experiments.Complex 1 is a 2D network structure constructed by Co(?)and Tipa.Complex 2 is a 2D network structure constructed by Cu(II)and Tipa.Complex 3 is a 2D network structure with 63 topologies constructed by Cd(II)and Tipa.Complex 4 is a 1D chain structure formed by Cd(?)and NO2-BDC,which is then connected with Tipa ligand to form a 2D layered structure.Meanwhile,There are interpenetrations between layers to form a 3D structure.In complex 5,Cd(?),Tipa and ONBA are connected with Cd-O and Cd-N to form a 2D layered structure with 63 topological structures.Complex 6 is a 2D layered structure formed by the coordination of Cu(?)with Ttpa and NO2-BDC.Complex 7 is a 2D layered structure formed by the coordination of Cu(?)with Ttpa and ONBA.Complex 8 is a 2D layered structure formed by the coordination of Zn(?)with Ttpa and NO2-BDC.The results of thermogravimetric analysis show that complex 1-8 have good thermal stability.The results of dye degradation showed that the complexes 1-3,5,7,8 synergistic with PMS had better removal efficiency for MO,the removal rates were 95%,95%,89.5%,94.2%,95.1%,91.1%,respectively.The specific capacitance of complexes 1 and 2 is 1278 and 1654.2 F·g-1 when the current density is 1 A·g-1.The adsorption results showed that the maximum adsorption capacity of complex 3 to K2Cr2O7 was 434.2 mg·g-1.