Syntheses, Structures And Properties Of Coordination Polymers Constructed From Dicarboxylate Ligands

Currently, coordination polymers (MCPs) have become one of the biggestconcerns for most researchers in all research areas, this is not only becausecoordination polymers have fascinating topologies and porosity, but also manypotential applications as functional porous materials in gas adsorption, catalysis,luminescence and magnetism. Although thousands of coordination polymers havebeen synthesized, and this number is still rising rapidly, but the design and synthesisof a desired functional coordination polymer is still a great challenge.Many factors can influence the synthesis of MCPs, and choosing organic ligandsis important in the construction of MCPs due to organic ligands’ small changes inflexibility, length, functional group position, and symmetry can lead to diversearchitectures and functions. So far, various multidentate organic ligands containing O-or N-donor atom have been used to construct novel MCPs, in which dicarboxylateligands are excellent structural builders and have been widely employed because theyhave the strong coordination ability and rich coordination modes.Moreover, to obtain CPs with desirable topologies and properties, differentmetallic cations have been tested. Among them, In(III) ions exhibit excellentstructural and coordinative flexibility, such as six-coordinated octahedra MO6,seven-coordinated pentagonal bi-pyramids MO7, and eight-coordinated polyhedraMO8. Indium coordination polymers have been proved to be effective catalysts in thegreen chemistry. Ni(II) and Pb(II) ions have attracted more and more attentionbecause they have a tendency to form varied polynuclear building blocks and thepotential to provide a stable framework structure.So we respectively selected1,4-H2bdc,4,4’-H2oba and1,3-H2adc as organicligands and In, Ni, Pb as metal centers to prepare novel coordination polymers andstudy their catalytic or magnetic properties. We hope to explore the methods of designing and synthesising structurally diverse and functional coordination polymers.The main research results are as follows:1. We selected1,4-benzenedicarboxylic acid (1,4-H2bdc) and4,4’-Oxybisbenzoicacid (4,4’-H2oba) as organic ligands and prepared two novel indium coordinationpolymers under solvothermal conditions, In(OH)(H2O)(1,4-bdc)(1) andIn(OH)(4,4’-oba)(DMF)(H2O)2(2). Compound1possesses a3D framework with thesquare-shaped channels that are built up from the infinite–In-OH-In-chains ofcorner-sharing In(OH)2(H2O)O4pentagonal bipyramids and1,4-H2bdc ligands.Compound2has a3D porous framework that is built up from the infinite–In-OH-In-chains of edge-sharing InO6octahedron and4,4’-H2oba ligands, the area of channel is5.7×5.82. Moreover, compound1and2exhibits good catalytic activity for thecyanosilylation of aromatic aldehydes, but the catalytic conversion of compound1ishigher than that of compound2. Compound2also shows excellent catalytic activityfor the Mukaiyama aldol reaction, but compound1do not have.(See chapter two)2. We respectively selected1,3-adamantanedicarboxylic acid (1,3-H2adc) as ligandand divalent metal ions Pb(II) and Ni(II) as centers. Three novel MCPs, namelyNi2Cl2(2,2’-bipy)2(1,3-adc)(3), Ni(1,3-adc)(2,2’-bipy)(4) and Pb(H2O)(1,3-adc)(5),have been successfully prepared under different solvothermal conditions. Compound3has a1D zigzag chain built up from dimeric [Ni2Cl2(2,2’-bipy)2]2+units and1,3-adc2-bridging ligands. The zigzag chain and its enantiomer alternately stack alongthe a axis through the π–π stacking interactions of bipy ligands. By changing themetal salt as Ni(OAc)2, compound4was obtained. Compared with compound3,Compound4features a1D zipper-like chain built up from NiO4N2octahedron and1,3-adc2-bridging ligands. But2,2’-bipy in the chain does not overlap, therefore theredoes not exist π–π interactions between the chains. Compound5shows a2D layerwith the rhombic windows along the c axis, built from the infinite bent Pb-O chainsand1,3-adc2-bridging ligands. Morover，compound3shows a high thermal stabilitylimit of425℃. Magnetic measurement shows that compound3and4displays theferromagnetic interactions.(See chapter three)...