Syntheses, Structures, And Properties Study Of Coordination Polymers Based On Novel Multi-carboxylate Betaines

In recent years, the coordination polymers based on multi-carboxylate acid, as one of the most intense studied areas for chemists, physicists, and materials scientists, have been extensively explored and realized for their aesthetics of crystalline architectures and their potential functions in luminescence, non-linear optics, adsorption, magnetism, and catalysis. In this paper, with the aim of construct of novel coordination polymers with intriguing structural motifs and good properties, three novel multi-carboxylate betaines (H2L1、H2L2、H2L3) and N-donor ancillary coligands were selected to prepare27complexes in the cooperation of metal ions. These complexes were characterized with X-ray single crystal diffraction, IR, elemental analysis. Furthermore, their thermal stabilities, phase purity, photoluminescence, as well as non-linear optics of some compounds were studied.1. Ten Zn(Ⅱ)/Cd(Ⅱ) coordination polymers with helical su8bunits was assembled from the mixed liagnds of H2L1(H2L2) and N-donor ancillary coligands. Complex1with homochiral triple concentric helical system has been obtained. Based on our understanding of the coordination with multi-concentric helical system, complex1with triple concentric helical system is the first example. Compound2displays a layered structure containing two kinds of helical chains. Compound3features a3D supramolecular framework embodying a type of supramolecular helical chain. Compound4exhibits a metal-organic ribbon structure with two kinds of helical chains. Compound5features a3D architecture in which a1D lemniscate shape pseudo meso-helix chain is observed. Compound6exhibits a2D achiral layer in which the1D (Zn-bpp)n helical chains are alternately arranged in a right-and left-handed sequence. Compound7displays a1D�'2D interdigitated architecture constructed from unique1D independent helical tubes. Compound8is a layered structure with two helical chains. Compound9is also a layered coordination polymer with two types of helical chains and features interesting2D�'3D interdigitated architecture. Compound10exhibits a3D3-fold interpenetrating framework with pillared helical-layers.2. Seventeen Ln(Ⅲ) coordination polymers with dinuclear SBUs based on H2L1(H2L2) and oxalic acid were hydrothermally synthesized. The single-crystal X-ray analyses of the complexes (11-21) reveal that they all have a2D layer structure with different dinuclear SBUs and crystallize in the same triclinic space group P-1. Two kinds of these complexes can be classified by their composition, meanwhile, four groups can be divided by different dinuclear SBUs in them. The average band length of Ln-O in each group and the coordination numbers of the Ln(Ⅲ) ions are decreased by the increase of atomic number. In general, the different structural features of11-21may be related to the ionic size of different lanthanide ions, the so-called "lanthanide contraction". In addition, the luminescent properties of Eu、Tb、Dy compounds have also been investigated in detail. The single-crystal X-ray analyses of the complexes (22-27) reveal that they all crystallize in the same monoclinic space group P21. The result of the analysis with the everage Ln-O band length and cell parameters confirmed the effect of "lanthanide contraction". As is known, energy transfers from one lanthanide to another lanthanide ion have been observed to enhance the luminescence intensity in heterolanthanide coordination polymers. We successfully obtained the functional luminescent MOF materials by doping isostructural Eu3+into Tb3+compounds to tune the emission colors by changing the doped Eu3+concentration. Therefore, the photoluminescence color of the Eu3+doped MOF canbe tuned from green-yellow to yellow, orange, and red-orange, and the corresponding CIE chromaticity coordinates change from (0.368,0.518) to (0.550,0.341) by changing the doping concentration of the Eu3+ions.