Synthesis,Structure And Properties Of Post-Transition Metal Phosphonate Complexes

As an important class of coordination polymers,metal phosphate complexes not only have a variety of coordination modes,but also posses good chemical stability,showing potential application in different areas including proton conduction,gas storage and catalysis.This dissertation focuses on the synthesis and chemical properties of metal phosphate complexes.Under hydrothermal conditions,a series of novel transition metal phosphate compounds have been prepared by adjusting the temperature,pH and time of the reaction.In addition,their catalytic behavior of CO2 cycloaddition and other properties were also investigated.1.Under hydrothermal conditions,an organic phosphate H8L was selected as a ligand and a three-dimensional copper phosphate complex,Cu7(H1L)2(TPT)3(H20)61 was successfully prepared.In spite of a dense motif,the exposed Lewis acid and Bronsted acid sites on the surface of the compound endowed compound 1 with excellent catalytic activity for the CO2 cycloaddition reaction that is superior to many conventional MOF-based catalysts.Meanwhile,compound 1 also exhibits high-performance catalytic activity and selectivity for the ring opening of epoxides with alcohols at room temperature.2.When reacting organic phosphate ligand H8L and Cd(NO)3 4H2O in the presence of HF as mineralizer,a 3D Cd(II)phosphonate network Cd4(H4L)2(phen)4(H2O)4 2 was obtained.This compound shows superior adsorption performance of Congo red(CR)dye in aqueous solution,featuring rapid adsorption,high uptake and recyclability.And it was the first time for the phosphonate-based materials to be used as an adsorbent for the removal of the CR dyes.3.By introducing different nitrogen-containing auxiliary ligands,five novel transition metal phosphate complexes were obtained under hydrothermal reaction,Ni3(H2L)(4,4'-bipy)1.5(H2O)83,Ni3(H2L)(mdib)3(H20)4,Co3(H2L)(tpt)(H20)2 5,Co2(H4L)(2,2'-bipy)2(H2O)2 6,Co2(H4L)(2,2'-bipy)(H2O)7?Among them,compound 7 can be converted into two other Co(II)phosphonic acid complexes with different dimensions under the induction of water solvent and temperature:Co2(H4L)(2,2'-bipy)2(H20)6 8 and Co2(H4L)(2,2'-bipy)2(H2O)3 9.The change in the dimensions of compounds by the single crystal transformation is rare in the phosphonate complex.4.In addition,under solvothermal conditions,two porous uranyl organic compounds[(CH3)2NH2]4[(UO2)4(TBAPy)3]·18DMF·17H2O 10 and[(CH3)2NH2]4[(UO2)4(TBAPy)3]22DMF·37H2O 11 were successfully prepared.Compound 10 and 11 are both capable of effectively absorbing Cs+ from low-concentration aqueous solution.The adsorption mechanism was proposed by experimental characterizations and density functional theory(DFT)calculations.The high removal efficency would make them promising in applications of radioactive waste management.