Constructions And Properties Of MOFs Based On Naphthol Tetramic Acid Ligand

Metal-organic Frameworks（MOFs）is a new type of crystalline porous materials formed by the coordination between metals（metal clusters）and organic ligands.Due to its high specific surface area,complex and diverse topological structures,modifiable functional groups and special pore structure,it has shown great application value and development prospects in the fields of gas storage and separation,catalysis,chiral resolution,magnetism,luminescence and chemical sensing,which has set off a wave of research by domestic and foreign scholars in recent decades.The framework of MOFs materials is also diverse due to the different ways of connecting metals and organic ligands,which ultimately endows MOFs materials with unlimited possibilities in research and applications.With the continuous innovation of science and technology,people’s research on MOFs materials is no longer limited to the initial stage of functional group modification of organic ligands,topological structures design,crystal construction,and property applications.It is rapidly developing towards functional materials.In this paper,we used naphthyl tetradentate carboxylic acid（H₄L）as an organic ligand and used solvothermal method to react with two different metal sources,zinc nitrate and manganese acetate.By adjusting reaction temperature and time,material ratio,and solvent type,we successfully constructed two novel MOFs materials,and analyzed the structures and basic characterization of the properties.1.A Zn-MOF material with a three-dimensional structure was successfully constructed using transition metal Zn（NO₃）₂·6H₂O and naphthyl tetra-acid ligand H₄L,[Zn₇(C₂₆O₈H₆)₃（NO₃）₂]·x Guest（compound 1）.Based on the structural characteristics,gas adsorption and separation performance were studied.Three ion exchanged compounds Zn-MOF-Co（compound 1’）,Zn-MOF-Ni（compound 1’’）,and Zn-MOF-Cu（compound 1’’’）were successfully synthesized using a metal ion exchange post synthesis strategy.Compared with the sample of compound 1,these three compounds showed a significant increase in their BET specific surface area.Subsequently,the adsorption and separation performance of CH₄,C₂H₆,C₃H₈,CO₂,and N₂ gases were studied on the exchanged compound 1’’’.The results showed that compound 1’’’exhibits good adsorption capacity for CH₄,C₂H₆,C₃H₈,and CO₂ gases.2.A Mn-MOF material,C₆₈H₆₀N₅O₁₈Mn₃（compound 2）,with an anionic skeleton was successfully constructed by using transition metal Mn（CH₃COO）₂·4H₂O,naphthyl tetra-acid ligands H₄L and triethylenediamine（DABCO）.Based on its unique anionic skeleton and the strongπ-conjugated system of H₄L,the fluorescence detection performance on metal cations and nitro explosives in ethanol solution was studied.The results indicate that even under the interference of other metal cations,Fe³⁺ions can still be selectively detected by compound 2.In addition,it also has good fluorescence sensing effect for nitro explosives.For 4-NP,the K_sv value can reach 2.39×10⁴M^-1,compound 2 exhibits good prospects for fluorescence detection applications.