Synthesis,Structure And Properties Of Co/Ni/Cd Coordination Polymers Based On Pyridine Dicarboxylate Ligands

Transition metal coordination polymers has received great attentions because of its novel topology and application in the gas adsorption and separation, drug delivery, catalyst carrier, optical materials and molecular magnetism. Therefore, to assemble transition metal coordination polymers through applying functional flexible organic ligands and transition metal ions, to explore the factors which influence the self-assembling process, and then study the relationship between the structure and properties of the products, is of great significance for the development of coordination chemistry.In this paper, ten new compounds have been hydrothermally synthesized and characterized by X-ray single crystal diffraction, X-Ray powder diffraction, Elemental analysis, Infrared spectroscopy, Thermo gravimetric analysis, Solid-state fluorescence spectroscopy and Magnetic properties determination. They are as follows with formula: [[Co3?2-pmipa?2?2-Hpmipa?2?dpa?2]n?1, 1D? {[Ni?2-pmipa??bpe??H₂O?]·?DMF?}n?2,2D? [Co?3-pmipa??1,3-dpp?]n?3,3D? [M2?3-pmipa?2?1,3-dpp?·2H₂O·DMF]n ?M=Co?4?,Ni?5?,2D+2D?3D? [Cd?3-pmipa??H₂O?]n·2nH₂O ?6,2D? {[Cd?3-pmipa??dpa?]·?H₂O?}n?7, ID? [Cd2?3-pmipa?2?4,4'-bipy?]n?8,3D? [Cd2?3-pmipa?2?bpe?·2H₂O]n?9,2D+2D?3D? {[Cd?2-pmipa??1,3-dpp?]2·2?H₂O?}n ?10,2D?The analytical results show that compounds 1 and 7 having 1D belt-like structure, compounds 2,6 and 10 featuring the 2D layer, compounds 4,5 and 10 exhibiting 2D layer structure interlocked into 3D network, and compounds 3 and 8 possessing the 3D pillared layer structure.Magnetic susceptibility measurements indicate a weak antiferromagnetic coupling between the adjacent Co?II? center among the{Co3} unit in compound 1, and a weak ferromagnetic interaction between the neighboring Co?II? ions in compound 3. The framework of compound 1-10 become to collapse at temperature of 321?,376?,438?, 395?,351?,497?,490?,463?,436? and 268?,respectively, which shows these compound are of good thermal stability. Compounds 6-10 have certain fluorescent properties, the corresponding excitation wavelength and the maximum emission peak were 430 nm and 541 nm,355 nm and 479 nm,350 nm and 461 nm,350 nm and 518 nm, 355 nm and 518 nm, respectively. The experimental X-ray powder diffraction data of compounds 1-10 are in accordance with the simulated ones, indicating that these compounds are of high purity. Coordination polymers assembled by pyridyl benzene dicarboxylate ligands and transition metal ions may possess good thermal stability, fluorescent and magnetic properties, thus may have potential applications in light emitting materials and magnetic materials.