Constructions and Properties of Coordination Polymers Based on Isomeric Pentacarboxylic Acid and Nitrogen Heterocyclic Carboxylic Acid Ligands

Author:Yan Yang Tian

Supervisor:zuo zheng ping


Degree Year:2019





Coordination polymers(CPs)are crystalline materials constructed by self-assembly of inorganic metal nodes and organic ligands through coordination bonds,which have the characteristics of both inorganic metal ions and organic molecules.Due to the changeable structure and excellent properties,CPs have become a new type of functional materials with great application potentials in the fields of gas storage and separation,dye degradation,catalysis,optics,magnetism,biology and so on.The construction of CPs is affected by many factors,such as central metal ions,organic ligands,reaction conditions and so on,how to synthesize new CPs with specific functions through reasonable design and regulation is the focus of researchers.This dissertation is concentrated on the construction of new functional CPs based on rigid V-type pentacarboxylic acid ligands and nitrogen heterocyclic carboxylic acid bifunctional ligands,exploring the appropriate self-assembly strategy to give full play to the important role of carboxylic acid group,azolyl group and pyridine group in the CPs to prepare new functional CPs,which takes into account the structural stability and novelty.The effects from ligand symmetries,functional group numbers and positional isomerization on the structure-property relationship of the CPs were also investigated.Based on the above ideas,in this dissertation,three isomeric rigid V-type pentacarboxylic acid ligands 2,4-di(3′,5′-dicarboxylphenyl)benzoic acid(H5L1),2,4-di(2′,5′-dicarboxylphenyl)benzoicacid(H5L2),3,5-di(2′,4′-dicarboxylphenyl)benzoic acid(H5L3)and a nitrogen heterocyclic carboxylic acid bifunctional ligand 5-(1H-1,2,4-triazol-1-yl)nicotinic acid(HL4)were selected,fifteen CPs with different structures and properties were constructed by hydro/solvothermal method.This dissertation is divided into the following six chapters:Chapter 1:The concept,design and synthesis strategy as well as application prospect of CPs are briefly introduced.Chapter 2:Three dimensional CPs have been synthesized by using H5L1 and metal ions Cu(II)and Co(II)under solvothermal condition:{[Cu2(HL1)(H2O)2]·2DMF·2H2O}n(1),{[H2N(Me)2][Co2(L1)(DMA)]}n(2)and{[H2N(Me)2][Co2(L1)(H2O)]}n(3).CP 1 is a porous polar framework containing the firstly observed undecahedral nanocages.The channel of activated 1a is occupied by open metal sites and uncoordinated carboxyl groups,which shows good CO2 adsorption capacity and CO2/CH4 adsorption selectivity.The free(CH3)2NH2+ions exist in the channel of CP 2,which can be exchanged by MB+and RhB+cations in aqueous solution,therefore,2 can not only effectively adsorb MB+and RhB+dyes,but also adsorb and separate MB+/MO-and RhB+/MO-mixed anionic and cationic dyes.In addition,the variable temperature susceptibility of CPs 1-3 indicates that there is a strong antiferromagnetic exchange between adjacent metal ions.Chapter 3:Three fluorescent CPs with different dimensions have been successfully synthesized by using H5L1 ligands and d10 Cd(II)ions under solvothermal condition:{[Cd4(H3L1)4(H2O)12]·2.5H2O}n(4),{[H2N(Me)2]3[Cd(L1)]·2.5H2O}n(5)and{[H2N(Me)2][Cd2(L1)(DMA)]}n(6).The solid-state luminescence properties of CPs 4-6 show that all of them have excellent luminescent properties and nanosecond fluorescence lifetime.CP 6 can be used as a highly sensitive and reproducible fluorescence probe for the detection of Fe3+and nitrobenzene.Chapter 4:A 3D porous CP{[Cu2(HL2)(H2O)2]·NMP·2H2O}n(7),based on binuclear paddlewheel unit[Cu2(COO)4]was synthesized under solvothermal condition by using H5L2and Cu(II)ions.The activated 7a contains high density of exposed metal sites and uncoordinated carboxyl groups in the pores,which not only possesses good CO2 adsorption and separation ability,but also can be used as a recyclable heterogeneous catalyst with excellent catalytic performance and substrate selectivity for the cycloaddition reaction of CO2 with epoxides under mild conditions.Chapter 5:FourCPs:{[Zn3(L3)(OH)(H2O)5]·NMP·2H2O}n(8),{[H2N(Me)2][Zn2(L3)(H2O)]·DMF·H2O}n(9),{[Co5(L3)2(H2O)11]·2H2O}n(10)and{[Mn5(L3)2(H2O)12]·6H2O}n(11) were successfully synthesized under solvothermal condition by using H5L3 and Zn(II),Co(II)and Mn(II)ions.CPs 8 and 9 have good fluorescence properties,in which CP 9 shows highly selective and sensitive fluorescence detection and recognition performance for Fe3+,CrO42-,Cr2O72-and MnO4-in aqueous solution.The magnetic properties of CPs 10 and 11 indicate that both of them show antiferromagnetic behavior.Chapter 6:Four CPs based on different metal clusters were synthesized by using HL4 ligands containing triazole,pyridine and carboxyl groups with metal ions Cu(Ⅱ)and Co(Ⅱ)under solvothermal conditions:[Cu2(L4)3(H2O)(OH)]n(12),{[Cu(L4)(O)0.5]·CH3OH·2.5H2O}n(13),{[Co(L4)(H2O)0.5(DMF)0.5(NO3)0.5]·(Cl)0.5·DMF·2H2O}n(14)and{[Co2(L4)4(H2O)]·2DMA·2H2O}n(15).CPs 13-15 are 3D porous frameworks.The activated 13a,14a and 15a contain a lot of CO2 adsorption sites,including exposed metal sites and uncoordinated nitrogen atoms,therefore,they have good capture and separation ability for CO2.Compared with 13a and 14a,15a also contains a large number of uncoordinated carboxyl groups as potential CO2 adsorption sites in its pores,so it shows better excellent adsorption selectivity for CO2/CH4.The magnetic properties of CPs 12-15 indicate that they all show antiferromagnetic behavior.