Luminescent Sensing Investigation Of Porous Organic Frameworks

Metal-organic frameworks (MOFs) and Covalent Organic Polymers (COPs) are new porous organic frameworks. The research of these materials in adsorption and separation, gas storage has already been mature, but the application of these materials in luminescent sensing investigation is still in the stage of development. The MOFs and COPs selected in this work all have rich conjugated π system, which result in good fluorescence properties.The main study of this work is the materials as luminescent probe in detecting heavy metal ions, small organic solvents and nitroaromatic explosives.Details of this work are below:(1) UMCM-1and UMCM-1-NH2were synthesized by sovlothermal method and characterized by XRD and PL spectra of solid powder. The results indicate that the materials have strong luminescence. The PL properties of UMCM-1and UMCM-1-NH2sensing heavy metal ions in aqueous solution were investigated. The results show that UMCM-1and UMCM-1-NH2have good luminescence in aqueous solution, both materials are sensitive to Fe3+, UMCM-1-NH2shows better selectivity to Fe3+. (2) COP-6, COP-7and COP-9were prepared by Yamamoto-type Ullmann coupling reaction catalyzed by Ni(COD)2. The three COPs were characterized by FT-IR spectra, SEM, XRD, TGA, EA measurement. The results indicated that three COPs had the amorphous structure, with high thermal stability and strong luminescence. The PL properties of three COPs sensing heavy metal ions were investigated. The results showed the three COPs were sensitive to many different metal ions, Fe3+caused the most significant quenching effect. Especially, COP-9showed the better selectivity to Fe3+, with the concentration of Fe3+increasing, the PL intensity of COP-9was falling down.(3) The PL properties of three COPs sensing small organic solvents and nitroaromatic explosives were investigated. All three COPs can dectect acetone through many different small organic solvents. With the volume fraction of acetone increasing, the quenching effect is enhancing. COP-6and COP-7are also sensitive to DMAC, COP-9is sensitive to THF. All three COPs can dectect nitroaromatic explosives. With the concentration of nitroaromatic explosives increasing, the quenching effect of three COPs is enhancing. COP-6is sensitive to PA, while COP-7and COP-9are better sensitive to DNT.