Lonothermal Synthesis, Structure And Properties Of Nickel, Dysprosium Metal Coordination Polymers

Coordination polymers have received great interest because of the uniquestructure design and potential application, such as gas storage, separation, catalysis,light, electricity and magnetic properties, etc. Nowadays, researchers are constantlylooking forward to the different ways to construct functional coordination polymerswith special structures. Ionthermal synthesis is a kind of method, in which ionicliquids are used as solvent instead of water or organic solvents. Besides, ionic liquidscan also serve as reactants, template agents, and balance charges. Consequently, newstructures can be obtained in ionothermal synthesis which can not be constructed inhydrothermal and solvothermal conditions.We selected5-hydroxy isophthalic acid （H₂hip） and thiophene-2,5-dicarboxylicacid （2,5-tdc） as ligands, transition metal salt nickel acetate [Ni（OAC）₂·4H₂O] andnitrate of rare earth metal dysprosium [Dy（NO₃）₃·6H₂O] source of metals to constructtwo new metal organic coordination polymers in ionthermal synthesis conditions. Thetwo compound structures were analyzed and their thermal stabilities, magneticproperties and adsorption capacities were also characterized.This master thesis mainly involves in the following three parts:1. We synthesized ionic liquids,1-ethyl-3-methy limidazole salt bromine（[EMIM]Br）,1–butyl-3-methyl imidazole salt bromine （[BMIM]Br）,1-ethyl-3-methyl imidazole four fluorine boric acid salt （[EMIM]BF₄）,1-butyl-3-methylimidazole four fluorine boric acid salt （[BMIM]BF₄） and1-butyl-3-methyl imidazolesix fluoride phosphate （[BMIM]PF₆）. The five kinds of ionic liquids werecharacterized through infrared spectrometer （IR） and nuclear magnetic spectroscopy（¹H-NMR）.（in chapter2）2. Transition metals （Ni）5-hydroxy isophthalic acid coordination polymer: H₃O[Ni（IP）（MeIM）₂]·0.5H₂O1（MeIM=methyl imidazole, H₂hip=5-hydroxyisophthalic acid）. Compound1is a new anion2D layer structure, in which Ni atomhas six coordinations in the octahedral geometry in its asymmetric structure unit.Each four oxygen atoms of H₂hip ligand connected with metal nickel ions in theplane, and two nitrogen atoms in methyl imidazole ligands is as terminal atomsperpendicular to plane. The coordination model of the ligand, H₂hip, in compounds1is rarely reported in the metal coordination polymer, and metal nickel atom was thefirst case in this way. Ionic liquid,[EMIM]BF₄, decomposed in situ in the process ofreaction to generate methyl imidazole as ligand in1. The magnetic curve shows thatthe Ni （II） center exist obvious antiferromagnetic coupling effect.（in chapter3）3.Rare earths metal （Dy） thiophene-2,5-dicarboxylic acid coordinationpolymer:[EMIM][Dy（2,5-tdc）₂]2（EMIM=1-ethyl-3-methyl imidazole,2,5-tdc=Thiophene-2,5-dicarboxylic acid）. Compound2is a3D supramolecular structure. Inthe asymmetric structure unit of2, Dy atom has eight oxygen atoms in coordinationwhich are from six different2,5-tdc ligands to form a slightly distorteddodecahedron configurations. The analysis of its structural frame shows two Dy（Ⅲ）center is connected by four bridge carboxylic oxygen atoms which come from fourdifferent2,5-tdc ligand to form a dinuclear unit. Such dinuclear units, acting as8-connected building blocks, are linked to their respective neigh bors, generating a3D structure with a topology represented by the Sch lfli symbol (4²⁴)（6⁴）. Emim⁺isfilled in the hole, playing the role of template agent and charge balance.（in chapter4）...