Design, Synthesis And Performance Research Of Environmentally Functional Metal Organic Framework Materials

Metal-organic Frameworks(MOFs)is a type of multi-functional crystal material,which is self-assembled through organic linkers and metal ions.Until now,MOFs are widely used in the catalysis,gas storage,adsorption and separation,due to the precise tunability of structure,large specific surface,and various functional metal ions.In this paper,we synthesized5-hydroxy-1H-pyrazole-3-carboxylicacid(H₃L¹),1-carboxymethyl-5-carboxymethoxy-pyrazole-4-carboxylic acid(H₃L²)and 4-pyridylmethyl phosphonic acid(H₃L³)ligand.The complexes based on pyrazole-carboxylic-acid and pyridine phosphonic acid were synthesized and their applications in photocatalysis were studied.The main research contents and innovations are as follows:(1)Four MOFs were synthesized based on H₃L¹,containing:[Ln(HL¹)(phen)(NO₃)^-](Ln=Gd(1),Y(2),La(3)),[Cd(HL¹)(DMF)(H₂O)](4).All of these complexes were characterized by single crystal X-ray diffraction,PXRD,FT-IR and TGA.Structural analysis result reveals that 1-4 display two-dimensional layer.And 1-3 are isotructural structure,4shows a different layer structure.The ligand(H₃L¹)exhibited two coordination modes in these complexes.Under the visible light irradiation,complex 2-4 exhibit efficient and stable photocatalytic degradation activities against organic dyes within 90 min.The degradation rates of 2-4 for MB are 93.60%,86.19%and 96.70%,respectively.And the degradation rates of 2 and 3 for CR are 87.12%and 71.62%,respectively.(2)Three MOFs were synthesized based on H₃L²,containing:[Ln₂(L²)₂(H₂O)₆]·1.5H₂O(Ln=Gd(5),Y(6))and[Mn₃(L²)₂(H₂O)₆]·2H₂O(7).All of these complexes were characterized by single crystal X-ray diffraction,PXRD,FT-IR and TGA.Structural analysis result reveals that 5-7 display two-dimensional layer,5 and 6 are isotructural structure.The ligand(H₃L²)also exhibited two coordination modes in these complexes.Under the visible light irradiation,complex 5 and 6 exhibit efficient and stable photocatalytic degradation activities against organic dyes within 90 min.The degradation rates of 5 and 6 for MB are 91.13%and 92.04%,respectively.And the degradation rates of 5 and 6 for CR are 84.21%and 86.96%,respectively.(3)The coordination polymer,formula[Ni(L³)(H₂O)₃](8)was synthesized by H₂L³and Ni(OAc)₂.And it was characterized by single crystal X-ray diffraction,PXRD,FT-IR and TGA.Structural analysis result reveals that 8 displays wave-layered structure.Under the visible light irradiation,the degradation rate of 8 for Rh B was 54.22%,which was increased to 86.73%after adding H₂O₂within 200 min.