Syntheses, Structures And Properties Of Coordination Polymers Based On Novel Derivatives Of 1, 3-benzenedicarboxylic Acid Ligands

In recent years, with the development of overlap between metal-organic coordination polymer and many other disciplines, more and more scientists pay more attention to this field. As a new type of functional material, MOF materials have a very broad space for development and application prospect in many fields, such as optical material, gas adsorption and separation, magnetic materials, catalysis and proton conduction. As we all know, the complexes based on aromatic carboxylic acid ligands are very important. These complexes have become hot research topics for the chemical staff with many advantages, such as diversified structure, regulatory structure and unique properties. In this paper, with the aim of constructing novel coordination polymers with fascinating structural motifs and good properties, three novel derivatives of 1,3-benzenedicarboxylic acid ligands were selected to prepare 30 complexes with the cooperation of metal ions. These complexes were characterized by X-ray single crystal diffraction, elemental analysis and IR. Furthermore, their thermogravimetric stability, relative phase purity and photoluminescent properties of some compounds were studied. In addition, we also studied the metal cations and explosives detections of compound 26. The proton conduction properties of compounds 26 and 30 are also studied.In my paper, the main work includes the following two parts:1. Twenty-one metal-organic complexes with novel structure were obtained from the hydrothermal method through the 1-(3,5-dicarboxy)-benzyl-1,2-di(pyridine-4-yl)ethylene chloride(H2L1)ligand with Zn(NO3)2, Cd(NO3)2, Cu(NO3)2, Cu Cl2, Ni(CH3COO)2, Mn(CH3COO)2 and the Ln(III), namely: {[Zn(L1)Cl]×4H2O}n(1), {[Zn(L1)H2O]×NO3×2H2O}n(2), {[Zn(L1)(H2O)]×(NO3)0.5×(Cl)0.5×2H2O}n(3), {[Cd(L1)(H2O)(NO3)]×2H2O}n(4), {[Cd1.5(L1)(Cl)2]×2H2O}n(5), {[Cu(L1)(H2O)]×NO3×H2O}n(6),{[Cu0.5(L1)(H2O)]?Cl?3H2O}n(7), {[Ni(L1)(H2O)Cl]×4H2O}n(8), {[Mn(L1)(H2O)Cl]×3H2O}n(9), {[Ln(L1)(H2O)2.5(NO3)1.5]×(Cl)0.5×(H2O)1.5}n(Ln = Pr(10), Nd(11), Sm(12), Eu(13), Gd(14), Tb(15), Dy(16), Ho(17)), {[Ln 4(μ3-OH)4(L1)3(H2O)7]·(NO3)5·3H2O}n(Ln = Er(18), Tm(19), Yb(20), Lu(21)). Complex 1 displays a 2D layer with the four-coordinated ZnII and the ligand, then adjacent 2D layers form a 3D framework through π···π interaction by the adjacent benzene rings and double bond of carbon-carbon. Compound 2, 3, 4 and 6 display 3D 2-fold interpenetrating frameworks with the connection of center metal ions and ligands. In compound 5, the ligangs connect trinuclear Cd SBUs to form a 2D layer, then adjacent 2D layers form a 3D supramolecular framework by π···π interaction. Complex 7, 9 and 14 are 1D chains, which result 3D supramolecular structures through π···π interaction and the hydrogen bonding. Complex 8 features a 2D layer, the adjacent 2D layers form a 3D supramolecular framework through π···π interaction. The complex 18, the ligangs connect tetranuclear Er SBUs to form a 3D porous structure. Two 3D porous structures display a 3D 2-fold interpenetrating frameworks.2. A series of complexes with novel structure were obtained from the hydrothermal method through the 5-(3,5-dicarboxybenzyloxy)isophthalic acid hydrochloride(H2L2) and 5-(3,5-dicarboxybenzyloxy)isophthalic acid nitrate(H2L3) ligands with the Ln(III), namely: {[Ln0.5(L2)(Cl)0.5]}n(Ln = La(22), Pr(23), Nd(24), Sm(25), Eu(26), Gd(27), Tb(28), Dy(29)) and {[Eu0.5(L3)(NO3)0.5]}n(30). The structures of these complexes are similar, which display a 3D porous structure through dinuclear SBUs and the ligands. There are many free chloride ions or nitrate ions in the pores. The protonated functional amino groups are located on the surface of the pores. The luminescent properties of complex 26 and 28 have also been investigated. Eu-MOF(26) exhibits the sensing of Fe3+ and phenolic explosives molecular. In addition, the proton conductivity of compound 26 and 30 were evaluated under the same condition using a compacted pellet of the powdered sample. The results show that the complexes have good proton conductive properties and compound 30 possess a proton conductivity of 1.41×10-3 S·cm-1 at 85% relative humidity. At the same time, we find that the change of anions in holes has a certain influence on the proton conductivity.