Synthesis,Characterization And Properties Of Rare Earth Coordination Polymers With Micro/Nano-Structures Based On N-Containing Ligand

Coordination polymers?CPs? micro/nano materials have become one of a new type of nanomaterials due to their extensive application prospects in the fields of luminescence, biological analysis, catalysis and magnetic materials. It is of great significance to studing the synthesis method of rare earth coordination polymers,control the morphology, explore the growth mechanism and tap the potential application. In this thesis, CP core-shell nanoparticles with Gd-based CP?GdCP? as core and Eu-based CP?EuCP? as shell, gadolinium–based CP hollow nanospheres and yttrium–based CP microspheres have been successfully prepared with coordination compounds containing nitrogen ligands by solvothermal and microwave-hydrothermal route. The as-prepared products were characterized by various measurement techniques and explored effects of various reaction conditions. The luminescence properties, magnetic properties and the contrast agent of the product are mainly studied. This work may provide method and theoretical basis for the synthesis of other coordination polymers.The main contents of this thesis are as follows:?1? Coordination polymer core/shell structures: preparation and up/down-conversion luminescenceCP core/shell nanoparticles with Gd-based CP?GdCP? as core and Eu-based CP?EuCP? as shell have been successfully prepared through simple solvothermal and hydrothermal methods. Allantoin was employed as the organic building block without the assistance of any template. CP core/shell structures exhibited up/down-conversion luminescence and showed excellent NIR-to-NIR upconversion emission. T1 weighted imaging test results show that the CP core shell structure has obvious T1 imaging.?2? Gadolinium-based coordination polymers hollow nanospheres :preparation and characterizationGadolinium-based CP hollow nanospheres were successfully synthesized viacontrolling the reaction solvent, temperature and time with glycylglycine as ligand and Gd³⁺ as central ion and Yb³⁺ and Er³⁺ as dopant ions. After calcination at high temperature, the formation of the coordination of gadolinium-based CP hollow nanospheres has been converted to Gd₂O₃. A series of characterization methods were used to characterize the product. At the same time, the magnetic test and the upconversion test were also carried out, which showed that the sample have upconversion luminescence properties. Using nuclear magnetic resonance analysis software to measure the relaxation information and T1 weighted imaging of the products and the properties of the CP hollow nanospheres as contrast agent were discussed.?3? Yttrium-based coordination polymers microspheres : preparation and characterizationCP microspheres with fluorescence properties have been synthesized by controlling the temperature and the different concentration of Eu³⁺ with asparagine as ligands by microwave-hydrothermal route. Study on the fluorescence lifetime of products of different temperature, different doping ratio of the fluorescence intensity and fluorescence intensity at different temperatures. Experimental results show that when the Eu³⁺-doped amount is 5 %, the fluorescence intensity is strongest. By contrast, it will decrease with the doping concentration Eu³⁺ increaseing, even lead to the quenched phenmenon. CP microspheres with low temperature have a longer fluorescence lifetime and stronger fluorescence intensity. Furthermore, the lower the temperature is, the stronger of fluorescence intensity. It has the characteristics of fluorescence temperature sensitivity.