In Situ Synthesis And Characterization Of Rare Earth And Transition Metal Tetrazole Compounds

Hydrothermal （solvothermal） synthesis is regarded as a novel and rapid developmentalmethod for synthezing coordination complexes, as the high temperature and pressure arebeneficial to the synthesis of the complexes with novel structure and unique properties notfeasible in conventional conditions. And as a multidentate ligand, tetrazole is regarded as"universal ligand" for its abundant and flexible coordination model, the study of tetrazolecomplexes has received more and more attention. Four kinds of rare-earth tetrazole and transitionmetal tetrazole compounds were prepared in hydrothermal （solvothermal） reaction using therare-earth metals （La^Ⅲ, Nd^Ⅲ, Eu^Ⅲ, Gd^Ⅲ, Er^Ⅲand Yb^Ⅲ）, transition metals and nitrile ligands assubstrates. The resulting compounds were characterized by means of X-ray single diffraction,Fourier transformed infrared spectroscopy, fluorescent spectroscopy, thermogravimetric analysis,X-ray photoelectron spectroscopy, dielectric property analysis and X-ray power diffraction. Thedissertation is divided into the following several parts.Firstly, eight rare-earth tetrazole compounds [Ln（H₂O）8·3（p-TPD）·2（p-HTPD）·7H₂O],（Ln=La （1）, Nd （2）, Eu（3）, Gd（4）, Er（5）, Yb（6））,[Ln（H₂O）8·3（p-TPD）·6H₂O)],（Ln=Er（8）, Yb（9））were synthesized by in situ [2+3] cycloaddition reaction using cyanopyridine （4-cyanopyridineand3-cyanopyridine） and rare-earth nitrate （La^Ⅲ, Nd^Ⅲ, Eu^Ⅲ, Gd^Ⅲ, Er^Ⅲ, Yb^Ⅲ） as the rawmaterials. X-ray single crystal diffraction indicated that all the eight rare-earth tetrazolecompounds are ionic. As far as we know, this is the first series of rare-earth tetrazole which wassynthesized through the [2+3] cycloaddition reaction using the rare-earth ion as Lewis solid acid.The compound1,2,4showed a good relationship among the structure, dielectric constant anddifferential thermal. Meanwhile, the compound3exhibited good fluorescence property throughits fluorescence emission spectra.Secondly, an interesting2D novel tetrazole coordination polymer,[（4-C5H4N-CN4）Cu]·H₂O（7） with a novel two-dimensional structure that is constructed by a binuclear copper（I） tetrazoleunits which was prepared by in situ [2+3] cycloaddition reaction under hydrothermal conditionsin the presence of4-cyanopyridine, CuCl₂·2H₂O and MnCl₂·4H₂O. The X-ray single crystaldiffraction showed that the central copper atoms were adopted a relatively rare three-coordinationmode; the XPS result further confirmed the oxidation state of copper in the target compound is+1.In addition, two transition metal tetrazolium compounds [CuNa（Mitz）Cl]（10），[Cd·（4-tzba）·（bipy）·（H₂O）]n（11） were synthesized by in situ [2+3] cycloaddition reaction underhydrothermal conditions in the presence of Milrinone,4-cyanpbenzoic acid ligand and transitionmetal salt （CuCl₂·2H₂O, MnCl₂·4H₂O, CdCl₂·2H₂O）. The structure analysis indicated the centre metals of compounds10,11were adopted six-coordinate mode. Compound10is the firstheterometallic tetrazole complex which is constituted by main group metal and transition metalthrough in situ [2+3] cycloaddition reaction. The dinuclear subunit of Compound11is connectedto each other through the cadmium atoms and expands to give a three-dimensional coordinationnetwork.Finally, the three-dimensional zinc tetrazole compound [Zn（Mitz）Cl]n（12） which wasprepared by our experimental group presented excellent ferroelectric property from itselectromagnetic hysteresis diagram, which indicated the three-dimensional zinc teyrazoliumcompound could be used as a potential neutral ferroelectric material and applied to ferroelectricmaterial field.