Novel Lanthanide Coordination Polymers: The Designed Synthesis And Applications As Sensors

Lanthanide based coordination polymers are new kinds of organic-inorganic hybridmaterials, which with many unique characteristics and advantages, such as：structurecould be designed and tunable, pore size could tunable, higher thermal stability andstronger chemical stability, etc.Detection of fluorescent probes become hot topic of modern research in chemistry,biological medicine and materials science owing to the advantages of their rapidresponse and easily operation. Combining the unique luminescence characteristics oflanthanide, lanthanide-based sensing materials become ideal sensing materials, therefore,rare earth coordination polymers as fluorescent probe materials are paid more attention.Recently, the kinds of materials have been detected, such as organic moleculars, cationsand anions, which have important practical significance for people’s health. Withpeople’s environmental protection consciousness strengthened, the updating andupgrading of detection method of pollutants have become primary concerns of scientistsand environmental related workers. The traditional detection method needs not only thecomplex operation step but also the support of large electronic equipment, while，chemical detection methods have the feature of simple operation, highly sensitivity andwider applicable scope, etc. Considering all of the above, we give the series of rare earthfluorescent probe materials and through a homemade device to realize the sensitivity gasdetection of varieties of common kinds of amine, and give thoroughly research on the detection mechanism, and laid a solid foundation for the realization of new types of rareearth fluorescent probes applied in the areas of environmental and food detection.Firstly, we designed a traditional configuration of triangle ligand4-(5-pyrimidine)benzoic acid (HL), and synthesized under the solvent thermal conditions with rare earths,then we obtained large amount of vacant N point lanthanide based coordination polymer,EuL. Its exact structure is obtained by single crystal X-ray diffraction experiment, andthe purity of the product was confirmed by powder X-ray diffraction experiment.Applying EuL to common organic solvent system, we found that the fluorescencequenching in aniline. There was only166ppm of aniline left can cause the fluorescencequenching. We decided use the gas phase detection in view of its high sensitivity, weadopt the continuous detection device we designed and test the influence of amine toEuL fluorescence in gas phase, it was found that aniline could made EuL fluorescencequenching as long as10seconds, it provides a theoretical basis for further in-depth studyabout the quenching mechanism. The mechanism of fluorescence quenching process ofEuL shows that the position of amine light absorption and the location of the rare earthcoordination polymers EuL have been overlap, the higher degree of the overlap, thegreater influence of EuL have, aniline and ultraviolet absorption spectrum of EuL almostoverlap, so, EuL has highest sensitivity.The second part of the experiment was conducted for detecting polluting anion. TheF-ion can lead to fluorosis of bone and dental fluorosis and leukoencephalopathy.Phosphates would make water eutrophication form habs. This chapter is about the newsynthesized rare earth complexes [TbL2(H2O)3](NO3)(TbL). First of all, commonmonovalent ions were chosed, and the results found that in the common monovalentanion, TbL can realize the recognition of F-ions. In various phosphates, TbL’sphotoluminescence were quenched except sodium hypophosphite. State environmentalprotection administration limits on detergent products containing phosphate salt is notmore than1.1%, according to this article,5mg of TbL could sensing of the totalphosphate about9.5%, close to the national standard.The third part of the experiment is mainly to detection of cations. In this part, we synthesized a3d-4f mixed3D coordination polymer Cu3Eu2L6(NO3)6(EuCuL). Theexactly structure was confirmed by Crystral XRD and purity by Powder XRD. There is arare phenomenon is fluorescent regeneration. Based on this refluorescent, we fulfill thesensing of Cd2+cation.