Metal Organic Frameworks Based On Cyclotriphosphazene:Synthesis,Structure And Properties

Metal-Organic Frameworks?also known as Porous Coordination Polymers?are usually formed by coordination of metal clusters or metal ions and organic ligands.In recent years,metal-organic framework materials have attracted more and more attention by scientists,because metal-organic framework materials often have the characteristics of both inorganic compounds and organic compounds.Metal organic coordination polymers have large specific surface area and porous structure,therefore they have shown potential application prospects in selective gas adsorption and separation,fluorescence,drug delivery,catalysis and other fields.Cyclotriphosphazene is a compound containing N and P alternately connected to each other to form a ring.It has good thermal stability.The two chlorines on the phosphorus atom are very active and thus nucleophilic substitution reaction easily takes place,so the purpose of effectively regulating the performance of the synthesized complexes was readily achieved by substituting different groups.In addition,there are few reports on the flexible carboxylic acid ligands based on cyclotriphosphazene.Therefore,such ligands are selected for further study.The specific research contents are shown as following.1?The ligands of H₆L1?H₆L2 and H₁₂L3 were synthesized by substituting six chlorine atoms of cyclotriphosphazene with methyl 4-hydroxybenzoate,methyl3-hydroxybenzoate and dimethyl 5-hydroxyisophthalate,respectively,and fully characterized by ¹HNMR and FTIR.2?By substituting the reaction,two chlorine atoms in the cyclotriphosphazene are first substituted with 2,2'-hydroxybiphenyl.And then,the organic ligand were synthesized by a synthetic strategy of pre-MOFs functionalization,The five ligands,namely H₄L4?H₄L5?H₄L6?H₄L7?H₈L8,were synthesized and characterized by¹HNMR and FTIR.3?9 MOFs materials were synthesized from ligands H₆L1?H₆L2 and H₁₂L3 with the metal Pb²⁺and the metal Ho³⁺and so on,respectively.These MOFs were characterized by single-crystal X-Ray diffraction?FTIR?TGA?XRD and Fluorescence.4?Two MOFs materials were synthesized by solvothermal method with ligands H₄L7 and H₈L8 respectively.The two MOFs was characterized by single-crystal X-Ray diffraction?FT-IR?TGA and XRD.