Synthesis, Characterization And Application Of Coordination Polymers With Ligands Containing Nitrogen And Oxygen Atoms

The research on supramolecular self-assemblies, structures and properties of coordination polymers has become an important current topic in crystal engineering because of their structural diversities, unique physicochemical properties, and potential applications in catalysis, adsorption, separation, molecule identification, etc. The most effective route to control the array of molecule in a crystalline so as to get a perfect functional material is to build multiple-dimensional coordination polymer using a metal cation and an organic ligand as a building unit. The aim of this paper is to study the rule of the self-assembly of coordination polymers synthesized hydrothermally, and the structure and the related performances of the coordination polymers. Eighteen coordination polymers with novel structures have been synthesized by hydrothermal synthesis using the ligands containing N and O atoms, and their structures and the related performances have been investigated. They were characterized by means of elemental analysis, IR, X-ray single crystal diffraction and TG-DTA, and their related properties were studied. The application of Co( II) coordination polymer has been attempted in the reaction of synthesis of diphenyl carbonate by oxidative carbonylation of phenol.The coordination polymers with ligand of 3-(3-pyridyl) acrylate acid were prepared. Under the conditions of hydrothermal synthesis, six coordination polymers with novel structures, [Co(pda)2(H2O)2]n(l), [Ni(pda)2(H2O)2]n(2), [La(C8H6NO2)3]n(3), [Nd(C8 H6NO2)3(H2O)]n(4), [Cd (C8H6NO2)2]n(5), and {[Co3(tma)(pda)2(H2O)3]-H2O}n(6), were synthesized by the reaction of 3-(3-pyridyl) acrylate acid and transition metal cations or rare-earth cations. The results are as follows, (a) The coordination polymers (1) and (2)possess the structure of heterogeneity same crystal, while the structure of coordination polymer (6) is much novel: there are two modes of coordination of Co( II) in the same constitutional unit, In addition, coordination polymer (6) shows anti-ferromagnetic performance, (b) Because of weak acidity and difficult dissolution ability of 3-(3-pyridyl) acrylate acid, the conditions of hydrothermal synthesis are severe. Especially, pH value of the reaction system, reaction temperature, crystallization time and temperature-descent rate affect the crystal structure.The coordination polymers with mixed ligands of 3-(3-pyridyl) acrylate acid and SCN" were prepared. Two coordination polymers with novel structure, [Co(pda) (SCN)(H2O)]n (7) and [Cd2(SCN)2(pda)2(H2O)3]n-nH2O(8), were synthesized. The results are as follows, (a) As for the mixed ligands of 3-(3-pyridyl) acrylate acid and SCN", the conditions of hydrothermal synthesis are more complicated. The structure of the coordination polymers with mixed ligands is influenced directly by pH value and the feeding order of the reactants. A perfect crystal of a coordination polymer with mixed ligands is controlled by the concerted actions of many reaction factors, (b) Under the conditions of hydrothermal synthesis, as for Co2+ and Cd2+ cations with different hard or soft acidity, the coordination modes of SCN" are different. In addition, the coordination modes are also different at different temperatures. SCN" links the metal cations whose acidities are between soft acid and hard acid in the form of bi-dentate ligands. The coordination polymer (8) with a rare structure coordinated by both N atom and S atom possess a better fluorescence performance.The coordination polymers with the mixture of dicarboxylic acid ligands (2,6-naphthalic acid, 1,4-phenylenediacetic acid, 1,4-fumaric acid, and adipate) and the ligands containing N atoms (4,4'-bpy, 1,10-phen and imidazole) were prepared. Seven coordination polymers with novel structures, [Co3(2,6-nda)3(4,4'-bpy)1.5]n(9), [Co(C12 H6O4)(1,10-phen)]n(10), [Nd2(C6H8O4)3(H2O)2]n-n(4,4'-bpy)(11), [Eu2(C6H8O4)3H2 O]2)n-n(4,4'-bpy)(12), [Co(C1oH804)(4,4'-bpy)]n nH2O(13), [Ni2(C10H8O4)2(l,10-phen)2 (H2O)2]n(14), and [Cd(C2H2O4)(Im)3]n-2nH2O(15), were synthesized under hy...