Synthesis,Crystal Structures And Properties Of Metal Phosphonate Coordination Polymers With Mixed Ligands

In this work,three metal phosphonate functional materials,[Zn（L₁）（2,2’-bipy）]·H₂O（1）,[Ni（L₂）（2,2’-bipy）₂（H₂O）]·H₂O（2）,[Cu（L₂）₂（2,2’-bipy）]·V₂O₅（3）,were innovatively synthesized under hydrothermal conditions by employing risedronic acid（H₅L₁=C₅H₄NCH₂C（OH）（PO₃H₂）₂）or 4,4’-biphenyl-diphosphonate monoester（H₂L₂=（C₂H₅O）（OH）OPCH₂（C₆H₄）₂CH₂PO（OH）（OC₂H₅））as phosphonic acid ligands and 2,2’-bipy as the second ligand.The crystal structure,thermal stability and fluorescence properties of compounds 1-3 were systematically characterized by X-ray single-crystal diffraction,X-ray powder diffraction,infrared spectroscopy（IR）and thermogravimetric（TG）analysis.The luminescence properties of compound 1 have been studied by using fluorescence spectroscopy.The catalytic properties of metal phosphonate materials have been studied in our group for the first time,and the catalytic properties of compound 3 was discussed in this work.In addition,we have done a deep research on the synthesized compounds 4-6 in this paper,[Cu（L₂）（4,4’-bipy）₂]（4）,[Cd（L₂）（2,2’-bipy）（H₂O）]·H₂O（5）and[Cd（L₂）（2,2’-bipy）₂（H₂O）]·H₂O（6）.Based on the previous work,the rules of crystal growth for metal phosphonate have been further explored and the powders with high purity were obtained.In addition,the catalytic properties of compound 4 and the recognition properties of compound 5 and 6 were investigated,so that the work has been further improved.X-ray diffraction analysis exhibit that compound 1 features a 1D supramolecular structure byπ-πstacking interactions,The luminescence properties of compound 1 indicate that they are good luminescent materials.Compound 1 has been realized for ions recognition properties.Compound 2 features a 1D supramolecular structure byπ-πstacking interactions.Compound3 exhibits 2D layered structures.Compound 3 and 4 have good properties in catalyzing the ketalization reaction of cyclohexanone and ethylene glycol.Compound 5 and 6 perform well in the selective recognition of Cr³⁺、Cr₂O₇^2-and CrO₄^2-in the polluted water,and the recognition mechanism was further investigated in this paper.