Synthesis And Properties Of Sulfonic Acid And Phosphoric Acid Metal-Organic Frameworks

MOFs are inorganic-organic hybrid materials,which are composed of metal ions or metal clusters and organic ligands through coordination bonds.It has broad application prospects in proton conduction and luminescent probe.In this paper,two phosphoric acid ligands were synthesized by the modified Mannich reaction.Four MOFs were prepared by using L1,L2,L3 and 1,2,4-triazole.The proton conductivity and luminescence properties were investigated,and the mechanism of proton conductivity were explored as follows:1.Compound 1 has been synthesized based on L1,oxalic acid,2,2-bipyridine and cadmium nitrate.Compound 1 has 2D structure with multiple H bonds.Compound 1 has the proton conductivity of 6.36×10-5 S·cm-1,and the Ea is 0.36 eV(Grotthuss mechanism).Composite membranes were prepared and their proton conductivity property were studied.The proton conductivity of 1@PVA-15 is 2.18×10-4 S·cm-1,and the Ea is 0.62 eV(Vehicle mechanism).Compound 1 is a luminescence probe detecting histidine in aqueous solution,and LOD is 1.0×10-8 M.2.Two kinds of phosphoric acid ligands were synthesized.Compound 2 has been prepared based on zinc chloride and L2.A large number of H bonds in the compound 2 contribute to proton conduction.Compound 2 has the proton conductivity of 3.43×10-5 S·cm-1 under 98%RH and 328 K,and the Ea is 0.41 eV(Vehicle mechanism).The proton conductivity of 2@PVA-10 is 2.78×10-4 S·cm-1 at 98%RH and 323 K,and the Ea is 0.62 eV(Vehicle mechanism).Compound 2 is a luminescence probe detecting Fe3+ in aqueous solution,and the LOD is 1.0×10-6 M.Compound 3 has been synthesized by cadmium nitrate and L3.Cd2+is coordinated with L3 forming 1D chain structure.The proton conductivity of 3@PVA-15 is 5.74×10-5 S·cm-1 at 98%RH and 363 K,and the Ea is 0.38 eV(Grotthuss mechanism).3.Compound 4 has been synthesized based on 1,2,4-triazole and zinc nitrate.Compound 4 is formed a 3D structure by the coordination of Zn2+and 1,2,4-triazole.Composite 1 has been prepared by encapsulating imidazole into compound 4.The proton conductivity of composite 1 is 1.51×10-4 S·cm-1 under 98%RH and 318 K,and the Ea is 0.54 eV(Vehicle mechanism).The proton conductivity of 1-PVA-10 to 1.23×10-4 S·cm-1,and the Ea is 0.12 eV(Grotthuss mechanism).Compound 4 can as luminescence probe detecting Fe3+ in aqueous solution,and the LOD is 1.0×10-7 M.