Hydrothermal Synthesis And Electrochemical Properties Of Copper-lanthanide Coordination Polymers Based On Pyridine-2,3-dicarboxylic Acid

In this paper,by using copper and lanthanide ions as central metals,pyridine-2,3-dicarboxylic acid?2,3-H₂pydc?as main ligand,and N,N?-di?4H-1,2,4-triazole?hexanamide?dth?and N,N?-di?4H-1,2,4-triazole?-1,4-cyclohexanedicarboxamide?dtcd?as auxiliary ligands,fifteen coordination polymers?CPs?were synthesized under hydrothermal conditions,namely,[LnCu?2,3-pydc?2?adi?0.5?H₂O?3]·2H₂O [Ln = La?1?,Pr?2?,Nd?3?,H₂ adi =adipic acid],[Ln2Cu3?2,3-pydc?6?H₂O?10]·8H₂O [Ln = Sm?4?,Eu?5?,Gd?6?,Tb?7?,Dy?8?,Er?9?,Yb?10?,Lu?11?],[Ln2Cu3?2,3-pydc?6?H₂O?6]·xH₂O [Ln = La?12,x = 8?,Nd?14,x = 10?] and [Ln2Cu2?2,3-pydc?4?NO3??OH??H₂O?6]·2H₂O[Ln = La?13?,Nd?15?].They were characterized by X-ray single-crystal diffraction,elemental analysis,IR,X-ray powder diffraction,and thermogravimetric analysis,and their electrochemical properties were studied.CPs 1–11 show two types of three-dimensional?3D?architectures with different topologies.The adi anion is derived from the in situ hydrolysis of dth.In 1–3,the binuclear Cu2?2,3-pydc?4 and Ln2?COO?2 units are connected to each other to form a two-dimensional?2D?layer,and the adi anion is connected to the adjacent 2D layer to form a 3D framework.In 4–11,the trinuclear Cu3?2,3-pydc?6 units are regularly arranged to form a 2D supramolecular layer,and the rare earth ions connect the 2D supramolecular layers to form a 3D framework.CPs 12-15 show two types of 3D structures with different topologies.In 12 and 14,the Cu?2,3-pydc?2 and Ln2?COO?4 units are connected to each other to form a 2D layer,and the adjacent 2D layers are linked by Cu?2,3-pydc?4 into a3 D framework with one-dimensional?1D?channels.In 13 and 15,the LnIII ions bridge the 1D chains based on 2,3-pydc and CuII into a 2D layer,and the nitrate and hydroxyl anions connect the adjacent 2D layers to produce a 3D frameworkwith 1D channels.