Synthesis, Crystal Structure And Properties Of Metal-organic Coordination Polymers Based On Aromatic Multi-carboxylate And Multi-pyridine Ligands

Nowadays the design and synthesis of new metal-organic coordination polymers is animportant subject for their potential applications in gas adsorption, separation, optical,magnetism, and so on. The self-assembly of metal-organic coordination polymers can berealized through metal ions and the ligands as the components which can be pre-designed.Therefore, it is important to design and synthesize organic ligands for obtaining the desiredmetal-organic coordination polymers.In this paper, we designed the multi-carboxylate and multi-pyridine ligands, due to theirlarger structures and polydentate abilities to form the complexes with big cavity and novelstructures. Four large skeleton aromatic ligands are synthesized, seven metal-organiccoordination polymers are constructed with the synthesized ligands and seven metal saltsunder solvothermal method. The structures and properties of the complexes are characterizedthrough X-ray single crystal diffraction, elemental analysis, powder diffraction,thermogravimetric analysis, fluorescence analysis, and other methods. The detailed contentsand results are outlined as follows:1.3,3′,5,5′-tetra(^4-formyl-phyl)-2,2′,6,6′-tetramethoxyl-1,1′-biphenyl （ligand L1）,3,3′,5,5′-tetra(^4-formyl-phyl)-2,2′,6,6′-tetrahydroxyl-1,1′-biphenyl （ligand L2）,3,3′,5,5′-tetra(^4-pyridinyl)-2,2′,6,6′-tetramethoxyl-1,1′-biphenyl （ligand L3） and3,3′,5,5′-tetra(^4-pyridinyl)-2,2′,6,6′-tetrahydroxyl-1,1′-biphenyl （ligand L4） are synthesizedthrough iodination reaction, C-C coupling, and other multi-step reactions using1,3-dimethoxybenzene,^4-methoxycarboxylphenylboronic acid,^4-pyridinylphenylboronicacid, and so on. Their structures are determined by¹H NMR,¹³C NMR, elemental analysisand so on, and the crystal structures of ligand L3and L4are determined by X-ray singlecrystal diffraction.2.[La₂(L1^4-)(L1^2-)·4H₂O]n,[Ce2(L1^4-)(L1^2-)·4H₂O]n,[Pr₂(L1^4-)(L1^2-)·4H₂O]n,[Nd2(L1^4-)(L1^2-)·4H₂O]nand [Sm2(L1^4-)(L1^2-)·4H₂O]nare synthesized under solvothermalmethod based on ligand L1and LaCl₃·7H₂O, Ce（NO₃）₃·7H₂O, Pr（NO₃）₃·7H₂O,Nd（NO₃）₃·7H₂O, Sm（NO₃）₃·7H₂O, respectively. And then their structures and properties arestudied by X-ray single crystal diffraction, powder diffraction, thermogravimetric analysis,elemental analysis, fluorescence analysis. 3.[Zn₂（CH₃COO）₄（L₃）·H₂O]nare synthesized based on ligand L3andZn（CH₃COO）₂·2H₂O under solvothermal method. In the same way,[Ni（bdc）（L3）·2H₂O]naresynthesized with ligand L3, H₂bdc, and Ni（CH₃COO）₂·2H₂O. And then their structures andproperties are studied by X-ray single crystal diffraction, powder diffraction,thermogravimetric analysis, elemental analysis, fluorescence analysis.