Synthesis, Structure And Properties Of Functional Coordination Polymers And Inorganic-Organic Hybrid Materials

Recently, the new research fields in the crystal engineering contain inorganic-organichybrid material, microporous material, monomolecular magnet and coordinationpolymers, et al. The research of the structures and properties of the novel systems can notonly rich the studies of the theory and experiment of the syntheses chemistry, but alsoextend the application prospect in electronic, optics, magnetism, catalysis and biologysimulation. According to the principle of crystal engineering, it is possible that rationaldesign and synthesis of crystalline materials by selecting certain geometric metal ionsand special organic ligands. At the same time, crystalline materials can be endowed withoptics, electric, magnetism, enantioselective separation and catalysis by selectingfunctional metal ions and organic ligands with functional groups. The aim of this work isto design and synthesize a series of coordination polymers and inorganic-organic hybridmaterials using hydrothermal techniques. Their luminescent, magnetism and adsorptionproperties were also studied.In the first chapter, the concepts, methods, histories and new developments ofcoordination polymers and inorganic-organic hybrid materials are concisely introduced.At the end of this chapter, we pointed out the importance of the search project andsummarized the important results obtained in the thesis.In the second chapter, a two-coordinated Cu(I) supermolecular coordination complex[Cu2(bipy)(H2L)2] MOC-1 (H3L = cyanuric acid, bipy = 4,4′-bipyridine) was synthesizedusing 4,4'-bipy and cyanuric acid under hydrothermal conditions. The supramolecularframework of MOC-1 is constructed through the adjacent Cu(I) dimer units connected byhydrogen bonding interactions. Complex MOC-1 shows intense yellow emission uponexcitation with UV light in the solid state, photoluminescence mechanism of complexMOC-1 is investigated in detail. A coordination polymer Co(QA)·(H2O)2 (H2QA=quinolinic acid) MOC-2 with 1D double-chains structure has been prepared usingquinolinic acid as ligand. In the structure of MOC-2, each Co(II) is surrounded by fouroxygen atoms and two nitrogen atoms from two QA-anions and two coordination watermolecules, resulting in 1D double-chains structure. These 1D double-chains are furtherassembled together through hydrogen bonding interactions into a 3D supramolecularframework. The weak antiferromagnetic interaction exists between Co(II) ionsintrachain.As has been well established, the lanthanide ions behave as hard acids and preferoxygen to nitrogen donors, while d-block metal ions are borderline acids having a strongtendency to coordinate to N-donors as well as O-donors. Therefore, a typical approach toconstruct 3d-4f heterometallic frameworks is self-assembly of mixed metal ions andproper ligands containing mixed-donor atoms. On this regard, in the third chapter, wealso chose quinolinic acid as the bridging ligand and prepared three isostructural novel3d-4f heterometallic coordination polymers with a 3D open-framework structure,[Ln2(H2O)4M2(H2O)2(QA)5]·nH2O (H2QA= quinolinic acid with Ln = Gd, M = Ni, n = 7(1);Ln = Gd, M = Co, n = 6.5 (2);Ln = Dy, M = Co, n = 6.5 (3)). These compoundspossess the isostructural 3D frameworks with 1D chair-like channels, which are occupiedby non-coordinating water molecules. The investigation of magnetic properties indicatesthe presence of weak antiferromagnetic interactions among the metal centers of 1 and 2.The design and synthesis of organic-inorganic hybrid compounds have receivedextensive interest due to their intriguing structural topologies as well as potentialapplications as functional materials. In the fourth chapter, a 3D frameworklanthanide-molybdyl material, [Gd(H2O)6Mo2O6(Hpydc)(pydc)]·H2O 1, is obtainedthrough an organic-inorganic self-assembly route under hydrothermal conditions. As theoxygen atoms on the surface of the polymolybdates are rather reactive, some lanthanidesions can readily incorporate into polymolybdates, resulting in precipitation instead ofcrystallization. One effective method is to improve crystallization through selectingappropriate ligands. On this regard, we chose pyridine-2,5-dicaroxylic acid as thebridging ligand and introduced the paramagnetic Gd(III) cation into the polymolybdate tosuccessfully generate a novel inorganic-organic gadolinium-molybdyl compound withdehydration-rehydration channel.Chiral inorganic–organic hybrid materials with microporous architectures arepotentially applicable in enantioselective separation and asymmetric catalysis. Therefore,it is of significance to incorporate enantiopure organic species that exhibit highhomogeneous catalytic activity for asymmetric synthesis into the framework structures ofmicroporous hybrid compounds. (S)-proline and its derivatives show highenantioselectivity in catalysis and they are able to afford good yields in many catalyticalreactions. In the fifth chapter, we chose the enantiomerically pure derivative of(S)-proline, N-(phosphonomethyl)proline, as a chiral building unit and successfullysynthesized a series of homochiral porous lanthanide phosphonates consisting ofone-dimensional triple-strand helical chains, [Ln(H2L)3]·2H2O, (H3L =(S)-HO3PCH2-NHC4H7-CO2H, Ln = Tb, (1);Ln = Dy, (2);Ln = Eu, (3);Ln = Gd, (4)).These right helical chains are connected together through hydrogen bonds interaction toform a 3D supramolecular framework with 1D tubular channel. Interestingly, thestructural characterization reveals that the one-dimensional left helical water chains existin the 1D channels. Meanwhile, the left helical water chains are anchored onto thetriple-strand right helical host chains. In addition, it is found that the obtained compoundsexhibit selective adsorption capacities for N2 and other solvent molecules afterdehydration. Compounds 1 and 3 also show strong green and red fluorescent emissions,respectively, in solid state at room temperature.