Fabrication And Fluorescence Sensing Performance Research Of Novel Coordination Polymers

Nitroaromatic explosives are widely used for military or industrial purposes,but in terrorist activities and effluent discharge,they pose a great threat to humans.Researchers in medical,environmental,military and other disciplines have begun to extensively research the methods of explosives detection and analysis.Nowadays,especially the activity of global terrorism requires an effective technique for detecting explosives,which is essential for defending the country,protecting the people and managing the environment.Fluorescent probe is simple to prepare,convenient to carry,and has a lower detection limit after exposing to analyte,which holds great promise in the field of identifying explosives.Additionally,coordination polymer materials are widely used as fluorescent sensing platforms because of their adjustable structure and high porosity.However,the structure of nitroaromatic explosives is similar,which poses an obstacle for fluorescent probes to specifically select a certain compound.In order to solve this problem,this paper introduced aggregation-induced emission molecules to solve the problem of fluorescence quenching,which is caused by the spontaneous polymerization of the probe,utilized the structural characteristics of the porphyrin,whose macrocyclic center can embed metal nodes,and synthesized two coordination polymers.When used as a fluorescent probe,they showed selective detection performance for trace amount of picric acid.The main contents are as follows:1.A three-dimensional coordination polymer Zn-TP was synthesized using a stepwise method.Firstly,tetra[4-(4'-carboxyphenyl)phenyl]ethylene and zinc nitrate hexahydrate were used as raw materials to form two-dimensional sheets through coordination bond.Then,solvothermal reaction was utilized to make the pyridine nitrogen atom in 5,15-bis(4-pyridyl)-10,20-diphenylporphyrin coordinate axially with the metal ion Zn^II,for supporting the formation of a three-dimensional coordination polymers Zn-TP.The apparent morphology of Zn-TP was observed to be long rod shape by a transmission scanning electron microscope,and the structure of Zn-TP was confirmed by the difference of infrared spectra.In addition,owning to the great thermal stability and fluorescence properties,Zn-TP was applied to the fluorescence detection of nitroaromatic explosives containing picric acid.The results reflected that based on the fluorescence quenching phenomenon,highly selective recognition of picric acid was realized by Zn-TP.2.First,anhydrous zirconium chloride was used to metallize the tetraphenylporphyrin,which has no coordination functional groups,then the metal Zr^IVand tetra[4-(4'-carboxyphenyl)phenyl]ethylene coordinated along the axis of tetraphenylporphyrin.they self-assembled and formed a two-dimensional coordination polymer Zr-TP metal-organic layer(Zr-TP MOL),which was applied to fluorescence detection of nitroaromatic explosives in liquid phase.The spherical shape of Zr-TP MOL was determined by a transmission electron microscope,and infrared spectroscopy,thermogravimetric analysis,and nitrogen adsorption and desorption curves were used to obtain the reason for the forming of spherical shape.After fluorescence tests,it was found that Zr-TP MOL had the ability to selectively recognize picric acid in an instantaneous response,and the fluorescence quenching effect of picric acid on Zr-TP MOL could be observed by naked eyes.which shows that Zr-TP MOL has practical application value for detecting picric acid.