| Rare earth coordination polymer（CP）has attracted wide attention due to their varied and novel spatial topology and excellent physical and chemical properties.Rare earth CPs,especially europium based CPs,exhibit excellent photoluminescence properties such as high color purity,narrow emission spectrum band,long fluorescence lifetime,which make it could be widely applied to new light sources,chemical sensing,biological images,nonlinear optics,optoelectronic devices and other fields.Recent studies reveal that CP is an excellent precursor for the preparation of materials with excellent properties,and the obtained materials exhibit better properties and higher activity than those prepared by other methods.In this thesis,a series of europium based CPs were prepared by a simple hydro/solvothermal or high pressure method with trifluorophenylboronic acid or phenylo boric acid.After that,the obtained products were decomposited under different atmospheres or ultra-high pressure and high temperature.The luminescent properties and the effects of high pressure on the synthesis and decomposition of europium based CPs were investigated in detail.The main contents of this thesis are as follows:（1）Preparation,luminescence and highly sensitive oxalate sensor of porous EuBO3microwafersUniform porous EuBO3 microwafers are obtained by calcining Eu-based CP which was synthesized by a facile solvothermal method without the addition of any mineralizer.The products were fully characterized.The diameter and thickness of the pure hexagonal EuBO3 microwafers are approximately 3μm and 0.6μm,respectively.Underλex=394 nm,characteristic emission of Eu3+is observed in the range from 570to 720 nm,which are attributed to the5D0-7FJ（J=0,1,2,3,4）transitions.Further investigations reveal that EuBO3 is a highly selective and sensitive sensor for oxalate,the limit of detection（LOD）is as low as 1×10-88 M.Overall,this study provide a convenient route for the synthesis of rare earth borate.To our best knowledge,it demonstrates that EuBO3 is a viable probe for sensing oxalate for the first time.（2）Preparation and fluorescence properties of carbon/europium fluoride composites under ultra-high pressure and high temperatureEu（NO3）3·6H2O was used as the metal center and 2,4,6-trifluorophenylboronic acid was used as reaction material,which was mixed and milled uniformly in a certain proportion.The reaction was carried out in an ultra-high pressure and high temperature circular piston device.The products were well characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,thermogravimetric analysis（TG）,Fourier transform infrared（FT-IR）and so on.It turns out that carbon/europium fluoride composites（C/EuF3）were synthesized under ultra-high pressure and high temperature.The results show that high pressure can not only promote the phase transition of europium fluoride structure,but also affect the fluorescence intensity and the length of fluorescence lifetime.Compared with orthorhombic phase europium fluoride（α-EuF3）prepared by hydrothermal method,the fluorescence lifetime was increased by 2 times for composites（C/α-EuF3）synthesized under 5.0 Gpa.（3）Synthesis,decomposition under high temperature and ultra-high pressure,and luminescence properties of europium-phenylboric acid CPOn the basis of the above research,europium-based CP micronflowers were built from Eu（NO3）3·6H2O and phenylboric acid under alkaline conditions via a simple hydrothermal method.The diameters of the micronflowers are approximately 1-2μm.The effect of reagent ratio,reaction time and reaction temperature on the morphology of the product was studied.The optimal conditions for the synthesis of europium-phenylboric acid CP were selected.Then,the precursor was decomposed in a ultra-high temperature and high pressure circular piston device.The effect of the pressure on the decomposition and luminescent properties was explored.The products were fully characterized and analysed.Interestingly,the europium-phenylboric acid CP decomposed into europium borate（EuB2O4）/C composites. |
