Synthesis, Characterization And Property Study Of Rare Earth Coordination Polymers With Micro/Nano-structures

Because of their superior performance, rare earth luminescent materials havebeen widely used in lighting, display, radiation discipline, and all aspects ofbiomedical applications.To a great extent, matrix materials affect the luminescentproperties of materials, because substrate materials can provide activated particles, asuitable crystal field and make them give corresponding emissions. According to thecomposition of substrate materials, the traditional luminous matrix materials aremainly concentrated on rare earth oxide matrix materials and rare earth fluoridematrix materials. In this paper, we synthesized several rare earth coordination polymermicro/nanoscale luminescent materials, using hydrothermal, solvothermal, microwave,and other method. The sample were characterized using various measurementtechniques and the synthesis mechanism, up-coversion performance, cytotoxicity, andso on were also discussed. This work may provide method and experimentalinstruction for the preparation of other rare coordination polymer micro/nanomaterials. It can used for other rare earth coordination polymer micro/nano materialssynthesis, applied research providing the theoretical basis and methods. The mainresearch content of this paper is as follows:(1) Synthesis and property study of rare earth-asparagine coordination polymernanoparticles with up-conversion luminescent properties.In this experiment, asparagine, glycol, Y(NO3)3·6H2O, Yb(NO3)3·6H2O,Er(NO3)3·6H2O were used as the ligands, solvenst, and the source of rare earth ions,respectively. The optimum synthesis conditions were determined by changing theratio of ligand to rare earth ions, reaction time, reaction temperature and so on. Highlyuniform rare earth coordination polymer nanospheres with up-conversion PL emissionwere synthesized through a solvothermal process at200oC for24h. Variousanalytical techniques were used to characterize the obtained products. The synthesismechanism was investigated and the cytotoxicity assay (MTT) of the material wasalso carried out. These results show that the size of the produced material is about50nm. The coordination polymer exhibits up-conversion luminescence, low cytotoxicity,and good dispersity in water.(2) Synthesis and property study of rare earth-allantoin coordination polymernanoparticles with up-conversion luminescent properties.In this typical experiment, allantoin, N,N-Dimethylformamide (DMF),Y(NO3)3·6H2O, Yb(NO3)3·6H2O, Er(NO3)3·6H2O were used as the ligands, solvents, and the source of rare earth ions, respectively. The optimum synthesis conditions weredetermined by changing the ratio of ligand to rare earth ions, reaction time, reactiontemperature and so on. Highly uniform rare earth coordination polymer nanosphereswith up-conversion PL emission were synthesized through a solvothermal process at200oC for24h. Various analytical techniques were used to characterize the obtainedproducts. The synthesis mechanism was investigated and the cytotoxicity assay (MTT)of the material was also carried out. The research results demonstrate that highlyuniform spherical nanoparticles can be synthesized through a solvothermal process at200oC for24h when the ratio of allantoin to rare earth ions is three to one and thevolum of glycol is25mL and allantoin is dissolved in2mL hot water. Thecoordination polymer exhibits up-conversion luminescence, low cytotoxicity, gooddispersity in water, good biocompatibility, and high drug-loading efficiency. Theobtained products may have wide potential application in biological area.(3) Synthesis, Performance and mechanism research of coordination polymerwith special structure.In our experiment, asparagine, deionized water, Y(NO3)3·6H2O, Yb(NO3)3·6H2O,Er(NO3)3·6H2O were used as the ligands, solvents, and rare earth ions, respectively.Without addition of any surfactant, polyhedron coordination polymer was synthesizedvia a hydrothermal process by changing the experiment conditions such as reactiontime. Uniform cross-linking micro spheres were obtained in a few hours. As the timewent on, products without specific morphology were obtained. The composition ofthe products varies with the morphology. We draw a conclusion that theup-conversion PL intensity of the product decreases and the product becomescrystallographic according to XRD pattern with prolonging of the reaction time.(4) Synthesis and performance study of flower-like rare earth coordinationhierarchical polymer.In our typical experiment, allantoin, N,N-Dimethylformamide (DMF),La(NO3)3·6H2O, Eu(NO3)3·6H2O, Tb(NO3)3·6H2O were used as the ligands, solvents,and the source of rare earth ions, respectively. Highly uniform layed rare earthcoodination polymer micro/nano particles were prepared by changing the ratio ofreactants, the amount of solvents, reaction temperature, and reaction time. Themorphology, structure, properties were characterized bu various measurements. Thereuslts show that flower-like coordination polymer was obtained when La3+only wasused as rare earth ions. Eu3+, Tb3+doped and Eu3+, Tb3+co-doped rare earthcoordination polymers were also prepared through the same process. The PLproperties of the obtained products were investigated.