Synthesis And Properties Of 4-Oxy-1,4-Dihydro-2,6-pyridine Dicarboxylic Acid Coordination Polymers

In this paper,nine novel complexes have been designed and synthesized based on 4-oxy-1-(4-dihydro-2-pyridine-6-pyridyl)dicarboxylic under hydrothermal conditions.The crystal structures of the complexes have been analysed by X-ray single crystal diffraction.The effects of hydrogen bond,?-? and other weak intermolecular forces on the formation of supramolecular were explained.The complex was characterized by elemental analysis,infrared spectra,fluorescence spectrum,as well as thermogravimetry.The main conclusions of this paper is as follows:1.When reacting with H2CDA(4-Oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid)and corresponding to the rare earth salts were employed under hydrothermal conditions,structure transformation phenomenon has happened.The ligand,H2CDA charged to its position isomer,enol type structure,H3CAM(4-Hydroxypyridine-2,6-dicarboxylic acid).The result that six new lanthanide(?)coordination polymers with the formulas[Ln(CAM)(H2O)3]n(Ln = La,1;Pr,2),{[Ln(CAM)(H2O)3]·H2O}n(Ln = Nd,3;Sm,4;Eu,5;Y,6)have been synthesized.The X-ray structure analyses show two kinds of coordination structures.Complexes 1-2 and 3-6 are isostructural,respectively.Complexes 1-2 crystallized in the monoclinic with C2/c space group,3-6 crystallized in the monoclinic with P21/n space group.In the two kinds of structures,H3CAM displays two different coordination modes.The Sm(III)and Eu(III)complexes exhibit the corresponding characteristic luminescence in the visible region at an excitation of 376 nm.2.When reacting with H2CDA(4-Oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid)and corresponding to Co?/Ln? salts were employed under hydrothermal conditions,structure transformation phenomenon has happened.The ligand,H2CDA charged to its position isomerism,enol type structure,H3CAM(4-Hydroxypyridine-2,6-dicarbox-ylic acid).The result that 3d/4f heterometallic two-dimensional(2D)net-works of {[Sm?Cou?2(CAM)(HCAM)2(H20)7]·2H2 O}n(7)and was obtained in a one-pot synthesis.The complexe crystallize in a monoclinic system within the centrosymmetric space group P21/c.No characteristic luminescence emission bands of corresponding Sm? ions for 7 was observed in the visible region,only the ?-?*and/or ?*-n transitions from the CAM 3-chromophore in the solid state and in DMF solution.