Synthesis And Properties Of Metal-Organic Framework Of Carbazolyl Carboxylic Acid

As a kind of porous materials,metal-organic framework materials?MOFs?have the advantages of large specific surface area,high porosity,and diverse structure.They have broad application prospects in gas adsorption,fluorescent materials,chemical sensors,and sewage treatment.It's the fact that the researchers pay more attention to the high-performance MOFs now.In this paper,a novel carbazolyl ligand,9-?3,5-dicarboxylic acid-benzyl?-9H-carbazole-3,6-dicarboxylic acid?H₄L?,was designed and synthesized.We synthesize 4 MOFs by solvothermal method totally.[Ni?H₂L??H₂O?₂]·2H₂O?1?and[Mg?H₂L??H₂O?₂]·6H₂O?4?have two-dimensional structure,while[Sr₂L?H₂O?₃]·2H₂O?2?and[Ca₂L?H₂O?₃]·H₂O?3?have three-dimensional structure.Compound 1 has good stability in water and can adsorb MB from mixed aqueous solution of methylene blue?MB?-methyl orange?MO?,exhibiting better selectivity.Compounds 2,3,and 4 have strong fluorescence emission and compound 2's structure is similar to 3,in which Cr³⁺can quenche the fluorescence of compound 2,and 2 has better capacity of adsorbing Cu²⁺.Meanwhile,Fe³⁺can cause the fluorescence quenching of compound 4.The reason for the fluorescence quenching of compound 4 may be that the electronic from where carboxylic acid group which is not coordinate with other atoms in the ligand transfer to the Fe³⁺by the excitation of the ultraviolet light.It may be also attributed to the part of the light energy is absorbed by Fe³⁺in the wavelength range.The limit of detection of Fe³⁺by compound 4can reach the?M level,which is a potential material for fluorescent recognition probes.