| Metal organic frameworks?MOFs?,also known as coordination networks?PCNs?or porous coordination polymers?PCPs?,are one-dimensional,two-dimensional or three-dimensional extended coordination polymers with high pore structure.Their networks are composed of metal centers and organic bridges.Because of its unique physical and chemical properties,such as:high specific surface area,high porosity,adjustable pore/hole size,good fluorescence purity and long fluorescence life,it has been widely used in many fields,such as luminescence,energy storage and conversion,gas separation/adsorption,chemical sensing,biomedicine and catalysis.In this treatise,three novel carboxylic acid coordination polymers were designed and synthesized based on the combination of monocyanoindole derivative ligand L1 and dicyanoindole derivative ligand L2 with the transition metal ion CD???.After a series of characterization,such as single crystal structure,element analysis,powder XRD,infrared analysis,thermal stability analysis and fluorescence test analysis,their application in the sensing direction of nitro compounds?NACs?was explored.The main research of this paper is as follows:1. The ligands L1{3-?5-bromo-2-?pyridin-4-yl?-3h-benzo[e]indol-1-yl?benzonitrile}were synthesized by solvent-free condensation of three components. In this paper,the first complex with 3D structure[C96H56N8O8Br4CD2]·H2O·2CH4O]was synthesized in situ by using L1 as organic bridge and 4-hydrated cadmium acetate.Under the excitation of 420 nm,the maximum emission peak at 435 nm is blue violet.The results show that the complex 1 has selectivity for 2,4,6-trinitrophenol?TNP?and 4-nitrophenol?4-NP?.The detection limits of TNP in the range of 0-0.035 m M and0.156m M-0.287 m M are 1.669×10-7M and 3.14×10-7M,and 4-NP in the range of 0-0.14 m M are2. The second complex[C96H56O8N8Br4Cd2]·3H2O·C3H8O was synthesized in situ by changing reaction conditions and solvents,using ligand L1 and solvothermal method. Complex 2 is a two-dimensional layered structure with high yield and good thermal stability3. In order to increase the coordination site,we introduced cuprous cyanide to replace Br group with CN group,and synthesized L2{1-?3-cyanophenyl?-2-?pyridin-4-yl?-3H-benzo[e]indole-5-carbonitrile}.The third complex[C50H28N6O4Cd]·2C2H6O was synthesized by the reaction of CD???with weak acid water and ethanol under high temperature and pressure.Complex 3 is a 3D network structure with good thermal stability,high fluorescence intensity and selectivity for 2,4,6-trinitrophenol?TNP?.When the concentration of TNP was in the range of 0-0.06 m M,the fluorescence intensity of complex 3 suspended in ethanol had a good linear relationship with the concentration of TNP.The fluorescence quenching constant was Ksv=2.27×106 M-1,and the detection limit was 1.841×10-8M. |
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