Synthesis And Properties Of Metal-Organic Frameworks Based On N-donor Azole Carboxylic Acids

Metal-Organic Frameworks（MOFs）are crystalline compounds based on metal ions or clusters linked to organic ligands in a certain way.In this thesis,we synthesized three N^-and carboxylic acid-containing ligands by exploiting the synergistic effect of N/O atoms in the synthesis of metal-organic frameworks.A series of complexes were synthesized by coordinating with metal ions through the synergistic effect of auxiliary ligands,and the structures and properties of the complexes were explored.In the second chapter,we synthesized the bifunctional imidazole carboxylic acid ligand 1,4-bis（1-N-acetic acid-4-imidazolyl）benzene,which has a flexible methylene carboxylic acid group that increases The diversity of coordination,and the imidazole group makes the coordination pattern more abundant.Using the synergistic effect of this ligand and auxiliary ligand（phen）,four complexes were synthesized:[Cd（L）（phen）₂·5H₂O（1）,[Cd（L）_0.5（phen）（Cl）]·2H₂O（2）,[Cd（L）]·2H₂O（3）,[Zn（L）]·H₂O（4）.Complex 1 adopts theμ₁-η⁰:η¹-mono-dentate coordination mode with Cd（II）ions through the carboxylic acid group on the organic ligand,forming a one-dimensional infinite zigzag chain,while the auxiliary ligand phen part only acts as a terminal The bidentate chelating ligand is coordinated to the Cd（II）atom.In complex 2,the organic ligand is connected to two Cd（II）atoms through a carboxylic acid group and an imidazole group,respectively.Similarly,the auxiliary ligand phen only acts as a terminal bidentate chelating ligand to coordinate with Cd（II）atoms,which is worth noting that a single Cl atom also participates in the coordination with Cd（II）atoms,which together form a 2D planar structure.Complex 3 is coordinated with Cd（II）atoms through a single organic ligand to form a three-dimensional framework with certain holes.The bifunctional function of complex 4 is coordinated with Zn（II）atoms to form a two-dimensional network structure.It is worth noting that when complex 1 was tested for fluorescence,it was found that complex 1 has a selective recognition function for nitro compounds（NACs）and Fe³⁺and Al³⁺ions,which has potential application value in monitoring environmental pollution.In the third chapter,we designed a polycarboxylic acid compound based on triazole as the parent and utilized this compound with N-containing organic ligands such as 1,2-bis（4-pyridyl）ethylene（BPE）,4,4-Bipyridine（BPY）,1,10-phenanthroline（Phen）,and carboxylic acid ligand terephthalic acid（pbda）,etc.,and metal ions were solvothermally synthesized seven new metal-organic framework materials:[Co₄（TZ244）₂（BPE）₃（H₂O）₂]·（DMF）·4H₂O（5）,[Co₃（TZ244）₂（BPE）₃（H₂O）₃]·H₂O（6）,[Co₃（TZ244）₂（BPE）₃（H₂O）₃]·H₂O（7）,[Co₂（TZ244）（BPY）_0.5(H₂O]·3H₂O（8）,[Cd₃（TZ244）₂（phen）（H₂O）₄]·2H₂O（9）,[Cd₂（TZ244）（pbda）_0.5（H₂O）₃]·（Et OH）2H₂O（10）,[Co₂（TZ244）（H₂O）₄]·5H₂O（11）.The structure of complex 5 is（3,3,4,4,6）The three-dimensional framework structure of the junction,in which a certain framework structure is formed by the ligand L,and the auxiliary ligand BPE acts as the supporting structure inside the framework,which together forms the three-dimensional framework of complex 5 Structure.The ligands and metal ions used in complex 6 and complex 5 are the same,but the synthesis conditions are slightly different.Its structural analysis shows that complex 6 is a three-dimensional material with a certain spatial structure.Complex 7 is composed asymmetric The coordination environment of the Co（II）atom in the structural unit is composed of an incompletely deprotonated TZ244 ligand,a BPY ligand,and a water molecule participating in the coordination.The structure of complex 8 is（5,4,4）The three-dimensional structure of the connection point.Complex 9 is composed of countless small planar structural units connected by carboxylic acid groups and has a certain three-dimensional layered structure.Complex 10 is composed of tetranuclear cadmium as the structural unit.A three-dimensional framework structure with certain holes is formed by using tetranuclear cadmium as the 5-connection point.Complex 11uses tetranuclear cobalt as the structural unit and tetranuclear cobalt as the6-connection point to form a planar network structure.In the fourth chapter,using 3-hydroxy-4-（4H-1,2,4-triazole-4-yl）benzoic acid as a ligand,through the coordination with metal ions Ni²⁺,Co²⁺,Cu²⁺,Four new metal-organic frameworks were synthesized:[Ni₃（L）₃（HCOO）₂]·2H₂O（12）,[Co（L）_1.5（H₂O）₂]·HCOOH·CH₃COOH（13）,[Co₃（L）₃（HCOO）₂]·DMF·H₂O（14）,[Cu（L）（H₂O）₂]·2H₂O（15）.Complex 12 is a three-dimensional framework structure with certain pores,and the porosity reaches 44.3%.Complex 13 is a 5-connection point with binuclear cobalt as a structural unit,and a three-dimensional framework compound with a certain spatial structure is formed through the connection of ligand L.Complex 14 has a similar spatial structure to that of complex 12.It is worth noting that the porosity of complex 14 reaches 47.0%.Complex 15 is a one-dimensional chain complex formed by the coordination of triazole groups with Cu²⁺,and a 3D supramolecular complex formed by abundant hydrogen bonds andπ-πstacking.Due to the high porosity of complex 12,the research on the adsorption performance of complex 12 showed that the specific surface area of complex 12 reached 1070.877 m²g^-1,and further research found that complex 12 had higher adsorption of CO₂performance,the adsorption capacities were 71.6 cm³g^-1,138.7 cm³g^-1and 237 cm³g^-1at 298 K,273 K and 195 K,respectively.It shows that complex 12 has great potential applications in CO₂adsorption and storage.This also provides theoretical support for further in-depth exploration of its properties in the future and points out the direction for the following work.