Coordination Complexes Supported By Pyridine-triazole Sulfhydryl N-heteroatom Ligands: Syntheses, Structures And Properties

In recent years, constructing the complexes with specific structures and propertieshas became increasingly popular. And the function of coordination compound isclosely related to its metal center ions, ligand properties and structure types.Metal-organic frameworks (MOFs) constructed from the ligands containingsulfhydryl-group or N-heterocycle (e.g. sulfhydryl imidazole, sulfhydryl triazole,sulfhydryl thiadiazole and sulfhydryl oxadiazole), not only have novel and flexibletopological structures, but have potential application in the fields of optics, ionsexchange, gas adsorption, magnetism, medicine, catalysis and nano materials.Therefore, this kind of ligand has attracted more and more chemists to research.For these reasons, we design and synthetize three flexible ligands:5-[(1H-1,2,4-triazol-1-yl)methyl]-1,3,4-thiadiazole-2(3H)-thione (tmttH),4-Amino-5-(1,2,4-trizole-1-yl)methyl-1,2,4-triazole-3-thione (a-tmttH),4-Amino-5-(1,2,3-benzotrizole-1-yl)methyl-1,2,4-triazole-3-thione (a-btttH), thentaking4-Amino-3-(3-pyridyl)-1H-1,2,4-triazole-5-thione (3-apttH) and5-(4-pyridyl)-1,3,4-oxadiazole-2-thione (pytH) as comparisons.The dissertation includes three parts as follows:1. Using tmttH as the ligand to self-assemble with metal ions Cd(II)、Zn(II)、Co(II)、Ni(II)、Pb(II) and Hg(II) under hydrothermal condition. We obtained six newcoordination complexes1-6: a four-fold interpenetrating3D framework [Cd(tmtt)2]n(1), a2D bilayer [Zn(tmtt)2]n(2), a2D crown-shaped network [Pb(tmtt)2]n(3),1Ddouble–helical chain structures [Ni(tmtt)2·(H2O)2]n(4) and [Co(tmtt)2·(H2O)2]n(5),and a mononuclear structure [Hg(tmtt)2](6). The crystal structures were confirmed bysingle crystal X-ray diffraction and revealed that the ligand tmttH has strongcoordinative abilities. And these complexes were determined by IR and elementaryanalysis. We also investigated the thermal stabilities of1-6and solid-statefluorescence properties of1,2,3,6, the ligand and discussed the influences of metalion to the structure of complex and structure to the thermal stability.2. By the use of pytH,3-apttH, a-tmttH and a-btttH as the major ligands, Cd(II) and Zn(II) ions as the metal centers, H2bdc as auxiliary ligand, we obtained six newcoordination complexes7-12under hydrothermal condition. We confirmed the crystalstructures by single crystal X-ray diffraction. The thermal stabilities and solid-statefluorescence properties of7-12were also investigated. Complexes[Cd2(pyt)2(bdc)·(H2O)]n·H2O (7) shows2D bilayer structure,[Zn2(3-aptt)2(bdc)]n(8)is2D network,[Cd4(3-aptt)4(bdc)2]n·8H2O (9) is2D ladder-like structure,[Zn2(a-tmtt)2(bdc)]n(10) presents2D grid network,[Cd2(a-tmtt)2(bdc)]n(11) and[Cd2(a-bttt)2(bdc)]n(12) possess similar3D structure. The results also indicated thatthe second ligand coordinate to metal centers and it is necessary in the process ofself-assembly of7-12.3. By using the cadmium complexes as the precursors, ethylene glycol and ethidenediamine as the mixture solvents, we got CdS samples. They were confirmed byPXRD. The structure and morphology of the powder could be controlled by adjustingthe ratio of the mixed solvents. Then we expect the photocatalytic properties andelectrochemical properties of the samples can be reaearched.