The Syntheses,structures And Properties Of The Metal-organic Compounds Based On Carboxylic Acid And Azole Derivatives Ligands

Metal-organic frameworks(MOFs)are mainly formed by coordination bonds between metal and organic ligands.With the characteristics of high specific surface area,high porosity,low density,and adjustable pore size,MOFs have extensive application prospects in gas adsorption,gas separation,drug carriers,fluorescence,and energy.Different organic ligands in MOFs play very important roles in the structural construction and performance regulation.Polycarboxylic acid and azole derivative ligands have many potential coordination modes and strong capabilities,which generate the MOFs have unique structures and wide potential applications.In this paper,a series of flexible polydentate nitrogen-containing ligands of 1,2-bis(imidazol-1-ylmethyl)-benzene)(o-bib),1,3-bis(imidazol-1-ylmethyl)-benzene)(m-bib),1,4-bis(imidazol-1-ylmethyl)-benzene)(p-bib),tris(4-(1H-imidazol-1-yl)phenyl)amine(TIPA)have been designed and synthesized.Six MOFs have been synthesized through these ligands and aromatic polybasic carboxylic acid 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid(H3TATB)and transition metals,including[Zn3(TATB)2(m-bib)3]·(DMF)1.5·(H2O)3(1),Fe(TATB)(m-bib)(2),[Fe(TATB)(p-bib)]·(H2O)(3),Co(HTATB)(p-bib)(H2O)2(4),[Cu(HTATB)(o-bib)]·(H2O)(5)and Fe(TATB)(TIPA)(H2O)(6).In addition,one ligand of 4-(((1H-1,2,4-triazol-3-yl)amino)methyl)benzoic acid(HTAMBA)containing carboxylate and azole groups has been designed and synthesized.Four coordination polymers based on HTAMBA have been synthesized,including Co(TAMBA)(H2O)(7),Mn(TAMBA)(H2O)(8),Fe(TAMBA)(H2O)(9)and Cd(TAMBA)(H2O)(10).The single crystal structures of ten compounds have been determined by X-ray single crystal diffraction,powder diffraction(XRD),thermogravimetry(TG)and infrared spectroscopy(IR).At the same time,the compounds have been used in experiments such as supercapacitors and solid fluorescence to study their performance.X-ray single crystal diffraction results show that compound 1 is a three-dimensional self-interpenetrating framework structure constructed by Zn(?),TIPA and TATB3-,which can be simplified into a 3,4-connected 65·7·813·9·10 topology..Compound 2 is a 1D linear structure constructed by Fe(?),m-bib and TATB3-,which can be extend into a 2D supramolecular structure through ?-? stacking interactions.Compound 3 is a 2D interpenetrated network constructed by Fe(?),p-bib and TATB3-ligands,such two 2D layers are interpenetrated into each other.Compound 4 is a 1D ladder constructed by Co(?),p-bib and HTATB2-.Compound 5 is a 2D network structure constructed by Cu(?),o-bib and HTATB2-,which can be simplified into a 44 topology.Compound 6 is a three-dimensional interpenetrating framework structure constructed by Fe(?),TIPA and TATB3-,which can be simplified into a 3,5-connected 54·64·73·9 topology.Compounds 7,8,9 and 10 are isomorphic structures,and all 1D linear structure constructed by metal center and TAMBA ligand,which can be expanded into a 2D supramolecular structure through?-? stacking interactions.IR and XRD analysis results show that compounds 1-10 have high purity.The good thermal stabilities of compounds 1-10 have been analyzed by TG.The compounds 1 and 10 have the potential of MOFs fluorescent devices,and compound 1 has good response to Zr4+and Cu2+.For supercapacitor performance tests,the compounds 2-9 have good electrochemical performances,low electrochemical impedance,and good cycle stability except for compound 5 in a three-electrode system.Compounds 2,3 and 6 have been assembled into asymmetric supercapacitors,which have the advantages of high capacity,low impedance,high cycle stability,high energy transmission efficiency,and high energy density.