Luminescence Modulation And Separation Application Of Rare-Earth Organic Tetrahedra

Designed-synthesis of metal-organic polyhedra(MOPs)and their application in sensing,identification,catalysis,and the stabilization of reactive species have attracted wide attention of scientists.Traditional metal-organic polyhedra are mainly composed of transition metals with fixed coordination configurations,and the metal ions are mostly serving only as the connecting elements and lack their own functions.Due to their unique 4f electronic configurations,rare-earth elements have shown excellent optical,magnetic and catalytic properties,and are widely used in modern industries such as display,imaging,laser,battery,ceramics,alloy,superconductivity,catalysis and so on.Therefore,the directed construction and functionalization of rare-earth organic polyhedra(REOPs)have important research significance.In this thesis,a series of rare-earth organic supramolecular tetrahedral and their polymer composites were prepared via coordination-directed self-assembly,and the properties of their luminescence and synergistic separation were studied.The specific contents are as follows:1.The regulation on the luminescent properties of the rare-earth organic tetrahedra based on the variation of electronic configurations on the ligand.Firstly,three tris(tridentate)ligands Ll-3 containing both electron donating/withdrawing groups were synthesized,which formed the Eu4(L1-3)4 tetrahedral REOPs with Eu3+ion via the coordination-directed self-assembly strategy.Based on theoretical calculations and photophysical studies,structure-function regulation principles between the fluorescence of the rare-earth organic tetrahedra and the electronic configurations of the ligand have been elucidated.We found that the assemblies with strong electron attracting groups displayed the strongest fluorescence emission.2.Luminescent polymers based on rare-earth organic tetrahedra and their applications in rare-earth separation.Polymer embedding provides an efficient strategy to optimize the performance of rare-earth luminescent materials.We designed and synthesized a Ln4(L4)4 supermolecular tetrahedra which has twelve styrene monomers on the outer surface,and then copolymerized it with non-functional monomers to realize the polymer embedding.It is found that the new composite not only preserves the porous properties of the polymer,but also improves the luminescence properties of the rare-earth organic polyhedra because of the site-isolation effect.In addition,due to the imprinting-effect and multivalent cooperative effect,this new polymer has exhibited potential application in rare-earth separation.This thesis not only provides a new strategy for the study of luminescence and adsorption separation properties of rare-earth organic polyhedra,but also provides a theoretical basis for the future functional applications of rare-earth organic polyhedra and their composites.