Syntheses, Crystal Structures And Properties Of Metal-organic Coodination Polymers Constructed From The2,5-Dihydroxy-1,4-Benzene Dicarboxylic Acid Ligands

Metal-organic coordination polymers constructed from metal ions andmultifunctional organic ligands as an important class of solid-state materials havepotential applications in gas-storage, photoelectron materials, magnetic materials andcatalytic properties. The research of metal-organic coordination polymers has beenattracted current attention in inorganic chemistry, solid state chemistry, and materialschemistry. The metal component may confer useful magnetic or optical electronicproperties, mechanical hardness, and thermal stability, while the organic componentoffers processability, a potential for structural diversification, and a range ofpolarizabilities.The combination of2,5-dihydroxy-1,4-benzenedicarboxylic acid （H4-DHBDC）ligand with lanthanide metal ions under various reactions produced elevenmetal organic coordination polymers, which are present in this dissertation.（a） Thereactions of Ln（NO3）3with2,5-dihydroxy-1,4-benzenedicarboxylic acid in DMFsolven under solvothermal conditions produce a series of isomorphous lanthanidecoordination polymers with the empirical formula{[Ln2（H2-DHBDC）3（DMF）4]（DMF）2}n（Ln=La（1）, Nd（2）, Sm（3）, Gd（4）, and Er（5））.（b） Six lanthanide（III）-2,5-dihydroxy-1,4-benzenedicarboxylate frameworks, namely,[Ln（H₂-DHBDC）_1.5（H₂O）₂]n（Ln=La（6） and Pr（7））,{[Nd（H₂-DHBDC）_1.5（H₂O）₃]（H₂O）}n（8）,{[Eu（H₂-DHBDC）（NO₃）（H₂O）₄]（H₂O）₂}n（9）, and {[Ln₂（H₂-DHBDC）₂（DHBDC）_0.5（H₂O）₃]（H₂O）₄}n（Ln=Gd（10） and Dy（11））,with four different structural types ranging from1D chain,2D layer to3D networks,have been synthesized under hydrothermal conditions. All compounds have beenstructurally characterized by single-crystal X-ray diffraction and infrared spectra. Thethermal stability of these compounds have also investigated. The adsorptionproperties and magnetic properties of some of the compounds have been studied indetail.This paper is consists of four chapters: the introduction, briefly introduced themetal-organic coordination polymers and the latest research progress metal organiccoordination polymers are present in Chapter1. The second chapter describes the synthesis, crystal structures, and properties of the five isomorphous{[Ln₂（H₂-DHBDC）₃（DMF）₄]（DMF）₂}n（Ln=La（1）, Nd（2）, Sm（3）, Gd（4）, and Er（5））compounds. Compound {[Ln₂（H₂-DHBDC）₃（DMF）₄]（DMF）₂}ncontains dinuclearLn₂（COO）₆clusters which are linked by the C₆H₅（OH）₂space to form a3Dframework. The3D framework shows1D open channels that accommodate the guestand coordinated DMF molecules. Gas adsorption measurements on compound Gd（4）indicate that the desolvated solid of Gd（4） adsorbs CO2into its pores and showsnonporous behavior toward N2. Magnetic measurements on compound Gd（4） indicatethat there is an antiferromagnetic interaction between Gd3+ions. Additionally, thepowder X-ray diffraction （PXRD） patterns of all five compounds have been provided.In the third part, six lanthanide（III）-2,5-dihydroxy-1,4-benzenedicarboxylateframeworks,[Ln（H₂-DHBDC）_1.5（H₂O）₂]n（Ln=La（6） and Pr（7））,{[Nd（H2-DHBDC）_1.5（H₂O）₃]（H₂O）}n（8）,{[Eu（H₂-DHBDC）（NO₃）（H₂O）₄]（H₂O）₂}n（9）, and {[Ln₂（H₂-DHBDC）₂（DHBDC）_0.5（H₂O）₃]（H₂O）₄}n（Ln=Gd（10） and Dy（11））,with four different structural types ranging from1D chain,2D layer to3D networks,obtained under hydrothermal conditions are presented. Compounds La（6） and Pr（7）are isomorphism and exhibit3D frameworks with the unique1D tubular channels.Compounds Nd（8） and Eu（9） are2D layered structure and1D zigzag chain,respectively, which are further extended to3D supramolecular frameworks throughextensive hydrogen bonds. Isomorphous compounds of Gd（10） and Dy（11） are3Dframeworks constructed from secondary infinite rod-shaped metal-carboxylatebuilding blocks containing infinite one-dimensional O–Dy–O–Dy–O chain. Themagnetic data of compounds Pr（7）, Nd（8）, Gd（10）, and Dy（11） have been investigatedin detail. In addition, elemental analysis, IR spectra, and thermogravimetric analysisof all compounds are also described. Finally, powder X-ray diffraction （PXRD）patterns of compounds Nd（8）, Eu（9）, Gd（10）, and Dy（11） have also been provided.The last chapter of the thesis present the summary and prospect of this work.