Constructions And Fluorescence Properties Of MOFs Containing Exposed N-Sites

In recent years,as a multifunctional new crystalline porous material,featured by properties of adjustable size and structure as well as addable functional groups,metal organic frameworks（MOFs）are widely applied in fields of gas storage,adsorption and separation,chiral resolution,catalysis and fluorescence sensing.Based on the capability that nitrogenous carboxylic acid ligands can design and synthesize MOFs material containing exposed N-sites,the interaction between exposed N-sites and the substance to be tested,including the electron transfer,can enhance the fluorescence response of MOFs material to the substance to be tested.The thesis will introduce the two different nitrogenous dicarboxylic acid ligands we selected.The Zn-MOF material l with double interspersed structure and the Zr-MOF material with superior water stability is synthesized by adding different regulators and solvent.In terms of their cationic and fluorescence sensing properties of nitroaromatic explosives,we conducted the studies as follows:（1）Taking V-type nitrogenous dicarboxylic acid as the ligand and triethylamine as the modulator,Zn-MOF material（Compound 1）with double interpenetrating structure is successfully synthesized,which is composed of 6-linked Zn₄O metal clusters and V-type nitrogenous dicarboxylic acid ligands,where the nitrogen in the ligand is exposed in the material for absence in the construction of skeleton.Based on the property of exposed N-sites,compound 1 can selectively detect Fe（III）in DMF solution by excluding the interference of other cations.Moreover,compound 1 has a good selectivity and fluorescence detection sensitivity for 2,4-DNP in DMF solution,whose K_sv value can reach7.2×10⁴ M^-1,which shows a high performance in MOFs material reported,representing the potential application of compound 1 in fluorescence detection.（2）Taking Z-type nitrogenous dicarboxylic acid as the ligand and benzoic acid as regulator,Zr-MOF material（Compound 2）with water stable property and exposed N-sites is successfully synthesized,which is composed of 8-linked Zr₆ cluster and Z-type nitrogenous dicarboxylic acid as ligand.Similar with the property of compound 1,compound 2 can selectively detect Fe（III）in aqueous solution by excluding the interference of other cations.Moreover,compound 2 has a good fluorescence detection sensitivity for nitroaromatic explosives in aqueous solution,whose the K_svvalues of TNP and 2,4-DNP can reach.5×10⁵ M^-1 and 2.8×10⁵ M^-1respectively,representing a perfect application prospect.Therefore,we can conclude that MOFs material with two exposed N-sites can be synthesized by adding different regulators and solvent,whose fluorescence detection performance is studied through exposed N-sites.