Design,Synthesis,Structure And Properties Of Transition Metal-Aromatic Phosphonate Coordination Polymers

In this work,by selecting an organic phosphonic acid containing a conjugated structural unit,2,4,6-trimethylenebenzene-1,3,5–trimethylenephosphonic acid（H₆L=C₆H（CH₃）₃（CH₂PO₃H₂）₃）.For the ligand,8 metal phosphonate coordination polymers which have not been reported in the literature were successfully synthesized under hydrothermal conditions.The crystal structure,thermal stability,luminescent properties,etc.of compound1–8 were studied by X–ray single crystal diffraction,X–ray powder diffraction,infrared spectroscopy（IR）and thermogravimetric analysis（TG）.The dye recognition performance of Compound 4 and the catalytic performance of cyclohexanone ethylene glycol ketalization reaction were investigated.The fluorescence recognition performance of the organic compound molecule of compound 5-7 was investigated by fluorescence spectroscopy.The chemical constitution formulas of compounds 1-8 are listed as follow:（1）Cu₂[（H₂L）（H₂O）₃]·2H₂O（2）Cu₂[（H₂L）（H₂O）₂]（3）Cu₄[（L）（H₂O）_3.5]·3.5H₂O（4）Cu₂[（H₄L）（4,4’–bipy）]（5）Zn[（H₄L）]·2H₂O（6）Zn[（H₄L）（2,2’–bipy）（H₂O）₂]（7）Zn[（H₄L）（2,2’–bipy）（H₂O）]（8）Cd[（H₄L）（1,4–Pyrazine）]Among the eight compounds synthesized,compounds 1,2,3 and 5 were synthesized by a direct reaction method,and compounds 4,6,7 and 8 were synthesized by the second ligand method.Compound 1-4 is a copper phosphonate coordination polymer,in which compound 1is a one-dimensional chain structure;compound 2 is a two-dimensional layered structure;compound 3 exhibits a three-dimensional skeleton structure,and compound 4 has a two-dimensional layered structure.Compound 5-7 is a zinc phosphonate coordination polymer,in which compound 5 is a two-dimensional layered structure;compound 6 is a cluster structure;compound 7 is a one-dimensional chain structure,and further forms a two-dimensional layered super by hydrogen bonding Molecular Structure.Compound 8 is a two-dimensional layered structure.The catalytic performance of cyclohexanone ethylene glycol ketalization of compound 4 and the recognition performance of methyl blue dye were investigated.Fluorescence spectroscopy was used to test the fluorescence recognition properties of organic molecules by compounds 5-7.The recognition performance of compound 5 on toluene and chlorobenzene organic compounds was explored.The results showed that compound 5 has a good recognition effect on 1,2,4-trichlorobenzene.The recognition performance of compound 6 on phenols,amines and aldehyde organic compounds was studied.Compound 6 has a good recognition effect on n-butyraldehyde.The structure of compound 7 and 6 is similar,and the fluorescence recognition performance of compound 7 on aldehydes is investigated.