Synthesis And Characterization Of Flexible Bis-nitrogen Heterocyclic Ligands Containing Aryl Group And Metal Complex

Metal-organic framework (MOFs) materials have drawn great attention because of their unique, structures. It owns great advantages compared to inorganic or organic materials, which have high orderly tubular structure, adjustable pour size, designable functional group and surface potential. Particularly, the search for new microporous materials with a hybrid metal-organic framework has became most popular research topics in functional materials field in recently years, fueled by the strong. incentive related to their use in catalysis, gas separation or strategic gas storage.The coordinated compounds with nitrogen heterocycle usually hold unique optical, magnetic, catalytic, biological activity and coordinated porperties to form coordinated polymers. There are wide application prospects in aspect of novel materials, molecular recognization, self-organization and so on. Also, due to the diverse coordinated fashions of nitrogen heterocyclic, which can form one-dimensional (1D), two-dimensional (2D) or three-dimensional (3D) network polymers with various geometry, a large number of coordinated polymers which formed by the reaction of nitrogen heterocyclic ligands with metals in different conditions have been reported. Furthermore, the magnetic, luminescent, ion-exchange properties of these complexes have also been researched.The ligand containing imidazoyl group not only has abundant coordinated ability, but also can easily form hydrogen bond. Therefore, it is important to study their coordinated properties and synthesize super-molecular compounds with hydrogen bond.1, 2, 4-triazole and its derivatives own structural characteristics and coordinated fashions of pyrazole and imdazole at the same time. They can serve as very good bridge ligands among metals. Furthermore, 1, 2, 4-triazole and its derivatives can show many characteristics, for example, abundant coordinated fashions, strong o donor groups, facile synthetic methods and so on, which made them become one of excellent choices in constructing novel functional multi-core metal polymers.Base on the above investigate background, we designed and synthesized six bis-imidazole ligands and six bis-triazole ligands. We also tried to prepare coordinated polymers by the reaction of these ligands with different metal salts. As a result, a metal-organic supermolecular framework was formed by self-organization and its structure was confirmed by X-ray single crystal diffraction. All synthesized ligands and polymer are reported first time and characterized by modern spectroscopy technology.This thesis consists of four parts:The first part of this thesis summarily introduced the development of researching bis-imidazole ligands and their metal complexes. The synthesis and application of bis-imidazole ligands containing aryl cores and their complexes were emphasized. In recent years, most of the aryl-heterocyle ligands are formed by the way of linking two or three imidazoles to benzene. The coordinated polymers formed by the reaction of these ligands with different transition metal ions generally own pores, some of which showed special properties. However, such kinds of network structures easily collapse once the solvent molecules inside the pores are removed. In view of the above dimerits, in this research, we attempted to stabilize the porous structures by large aryl systems like naphthalene or anthracene and enlarge porous size by increasing allyl bridges in order to get the novel properties. And then another summarization is given on the research of ligands containing 1, 2, 4-triazole and their complexes. Also, the synthesis and application of bis-triazole ligands containing flexible alkyl bridge and their coordination compounds were emphasized. Bis-triazole ligands containing aryl-core are seldom reported in the published literature.The second part of this thesis reported the synthesis of six new bis-imidazole ligands containing benzene, naphthalene or anthracene using hydroquinone, resorcinol, naphthalene-1, 4-dione, naphthalene-1, 5-diol, anthracene-9, 10-dione or anthracene-1, 4-dione as starting materials. All the products were comfirmed by melt point, IR, ¹H NMR and element analysis. Their aryl system and flexible alkyl bridge are gradually increasing than the known analogue. We can systematically study the effect of aryl system of ligands on the properties of coordinated complex. Such works provided a premise to study structure-property relationship.The third part of this thesis presented the preparation of six new bis-triazole ligands containing benzene, naphthalene or anthracene. The ligands were obtained by displacing the imidazole group in the second part with 1H-1, 2, 4-triazole. All the products were characterized by melt point, IR, ¹H NMR and element analysis. By comparing bis-imidazole ligands to bis-triazole ligands synthesized, we can explore the differences of coordinated ability between two kinds of ligands. The fourth part of this thesis showed a novel metal-organic framework supermolecule containing 3D geometry formed by the reaction between new bidentate ligand 1, 5-bis(imidazol-1-ylethoxy)-naphthalene and Zn(NO₃)·6H₂O. Its structure was confirmed by X-ray crystal diffraction. It belongs to trigonal and R-3 space group. a=22.8249(14)(?), b=22.8249(14)(?), c=14.8386(19)(?),α=90.00°,β=90.00°,γ=120.00°, V=6694.9(10)(?)³, Z=3, R_gt(F)=0.0640, T=291K. Each zinc atom is coordinated by six N atoms of imidazoyl groups derived from six different ligands. The coordination geometry of the zinc (â…¡) center is octahedronal. In addition, the complex was characterized by IR and TG-DSC analysis.