Construction Of Coordination Polymers With Unsymmetric Oxadiazole Or Triazole Derivative Ligands

On the focus of current hot research topic of coordination polymer, several un-symmetric ligands with functionalized oxadiazole or triazole groups were choosen and applied as predesigned molecular building blocks to achieve the controlled as-semblies of functional coordination polymers through modular synthetic methodology. A series of polymeric complexes were synthesized and structurally characterized, and their properties have also been investigated for the sake of exploiting the potential re-lationship between structures and properties. This thesis consists of six chapters.In chapter 1, the recent research progress of porous metal-organic frameworks (MOFs) was represented and their useful properties, such as magnetic ordering, opti-cal activity, catalysis ability, and microporosity, were also introduced. Then the re-search significance and main conclusion of this thesis were summarized.In chapter 2, four novel ZnII and CdII metal-organic coordination polymers based on a versatile building block 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol (4-Hpyt) have been successfully prepared under different conditions. The anionic ligand 4-pyt takes thioamide form in 1, 2 and 4; but the thiolate form in 3. Four types of coordination modes have been detected. Complexes 2 and 4 display large 1-D channels in which the solvents are accommodated. Their adsorption properties of solvent and nitrogen have been also investigated. In chapter 3, reactions of 4-Hpyt or 3-Hpyt with typical octahedral metal ions (CoII or NiII) generate a series of porous coordination polymers with the general formula of {[M(pyt)2(H2O)2]·(solvents)}n (5-10). These crystalline materials behave uniform 2-D grid-like host coordination frameworks with the inclu-sion of varied guest solvents, in one of which unusual water clusters are observed. Chapter 4 presents the structural assemblies of coordination polymers 11-15 by utiliz-ing the familiar metal ions with two flexible and versatile pyridinecarboxylate deriva-tive ligands as the anionic building blocks, namely, 5-(4-pyridyl)-1,3,4-oxadiazole-2- thioacetate (4-Hpyoa) and its 3-N-pyridyl isomer. These complexes display multifari-ous polymeric coordination frameworks, such as 1-D double-strand chain, 2-D ho-mochiral layer, as well as 3-D (3,6)-connected networks with anatase or rutile topol-ogy. Apparently, the metal centers and ligand spacers play a synergistic role in facili-tating the structural diversity. In chapter 5, a series of two-dimensional (2D) and three-dimensional (3D) MOFs 16–19 with unusual (3,6)-connected or 4-connected SrAl2 net topology are presented on the basis of a predesigned three-connected component bis(1,2,4-triazol-1-yl)acetate (btza). When properly treated with the familiar divalent metal ions, btza may perfectly furnish the coordination spheres for effective connectivity to produce diverse (3,6)-connected nets. In chapter 6, N-(3,5-bis(3-pyridyl)-1,2,4-triazole-4-yl)nicoti-namide (3-Hbptza) was employed to react with octahedral metal ions in virtue of ox-alate co-ligand, and two unprecedented architectures with (4,5)-connected net topol-ogy were afforded in virture of hydrogen-bonding (20?22) or coordination (23) inter-actions. The radii of different metal ions have significant influence on the coordina-tion modes of 3-bptza and the overall supramolecular networks.