Synthesis,Crystal Structures And Properties Of Transition Metal Phosphonate Materials

In this work,by selecting 4,4′–biphenyldiphosphonate bis（monoethyl ester）（H₂L=（C₂H₅O）（OH）OPCH₂（C₆H₄）₂CH₂PO（OH）（OC₂H₅））as the phosphonic acid ligand,2,2’–bipy,1,10–phen and 4,4’–bipy as the second metal linkers,we have been successfully synthesized five novel metal phosphonates under hydrothermal conditions.All the compounds were structurally characterized by X–ray single-crystal diffraction,X-ray powder diffraction,infrared spectroscopy,thermogravimetric analysis and and luminescence spectroscopy.The crystal structures,framework stabilities and luminescence properties have been investigated.In addition,the molecular recognition properties of compounds 1,4 and 5 in different organic analytes suspensions were investigated by the luminescent method.The chemical constitution formulas of compounds 1–5 are listed as follow:（1）[Cu₂（L）（2,2’–bipy）₂（CuCl₂）]·CuCl₂（2）[Cu（L）（1,10–phen）₂]·CuCl₂（3）[Cu（L）（4,4’–bipy）₂]（4）[Cd（L）（2,2’–bipy）₂（H₂O）]·H₂O（5）[Cd（L）（1,10–phen）₂（H₂O）]·5H₂OX-ray diffraction analysis exhibit that compounds 1 and 3 show 2D layered structures and compound 2 features a 2D supramolecular structure byπ–πstacking interactions.Compound4 features a 1D supramolecular structure through hydrogen bonding.Compound 5 can be described as a 3D supramolecular structure,which is assembled by three types ofπ-πstacking interactions and hydrogen bonding.TG curves of compounds 1–5 reveal that compounds 1 and 2 have the stabilized framework structures from room temperature to 200°C and 250°C,respectively.The molecular recognition experiments of compounds 1,4,5 showed that compound 1 may be potentially used for the sensing of DMF through the fluorescence method.And compounds 1,4 and 5have been realized for sensitive sensing of p–nitrophenol.