Construction And Properties Of Coordination Polymer Based On 5-(1-(Carboxymethyl)-Pyrazole)-Isophthalic Acid

Coordination Polymers（CPs）are novel materials composed of metal ions or metal clusters and organic ligands containing certain functional groups through coordination bonds.The synthesis of ligand polymers is affected by organic ligand,metal ions,reaction conditions（temperature,pH,solvent,etc.）and other factors,and the structure and functional groups of organic ligands play a key role in the performance of complexes.Nitrogen-containing carboxylic acid ligands with multiple active sites have become a research focus of coordination polymers due to their diverse coordination modes.They can be used to construct functional materials with steady structures and characteristics of adsorption,separation,fluorescence sensing,magnetism,catalysis and so on.In this paper,the organic ligand 5-（1-（carboxymethyl）-pyrazolyl）isophthalic acid（H₃L）was chosen as the research focus,which reacted with a variety of transition/main group metal ions by solvothermal method to obtain six complexes with different structures.Namely{[Cd₃（L）₂（H₂O）₅]·NMP·3H₂O}_n（1）,{[Pb₃（L）₂（NMP）₂·（H₂O）]·H₂O}_n（2）,{[Zn₄（L）₂（H₂O）₄（OH）₂]·3NMP}_n（3）,{[Zn₃（L）₂（H₂O）₂]·Diox}_n（4）,{[Co₃（L）₂（H₂O）₂]·Diox}_n（5）,{[Co₃（L）₂（H₂O）₄]·Diox}_n（6）.The complexes were systematically characterized by means of X-ray single crystal diffraction,infrared spectroscopy（IR）,thermogravimetry（TGA）and elemental analysis（EA）.The results showed that the organic ligand could construct coordination polymers with various structures and excellent properties through different coordination modes with various metal ions.In this paper,fluorescence test and water stability of complexes 1-4 were studied,along with the magnetic properties and antibacterial properties of complexes 5-6.The main contents are as follows:In the first part,The structure and basic properties of four new complexes constructed by organic ligand H₃L and metal ions（Cd（Ⅱ）,Pb（Ⅱ）and Zn（Ⅱ））by solvothermal method were introduced.Complex 1 formed a two-dimensional layered structure by Ligands and metal clusters of Cd（Ⅱ）.Complex 2 formed a two-dimensional layered structure by ligand and metal chain.Complex 3 formed a two-dimensional layered structure by the four-core Zn-cluster and ligand.Complex 4 formed a trikaryon Zn-cluster connected with ligand to form a two-dimensional layered structure.Fluorescence studies showed that complex 3 had high selectivity and sensitivity to Fe³⁺,CrO₄^2-and Cr₂O₇^2-in aqueous solution.In the second part,Two coordination polymers based on H₃L ligand and Co（Ⅱ）were constructed and their structures were characterized.Among them,complexes 5 and 4 were isomorphic,and complex 6 was a two-dimensional layered structure with metal cluster of Co（Ⅱ）and ligand,which the ligand had different coordination modes.The magnetic properties of these two complexes were studied,and the results showed that they had antiferromagnetic behavior.The antibacterial experiments showed that the antibacterial effect of complexes 5 and 6 on E.coli was basically the same,while the antibacterial effect of complex 5 on staphylococcus aureus was better.