Synthesis And Their Conversion Of Coordination Polymers Micro/Nano-structures Constructed By Organic Ligand With O And S

Over the past decades, coordination polymers(CPs) have attracted considerable attention as their unique structure and property have great potential technological applications in some fields, such as gas absorption and separation, heterogeneous catalysis, sensing and biomedicine etc. CP is composed of corresponding metal ions and organic linkers by self-assembly. According to the difference of center metal, it can be divided into three classes: rare-earth CP, transition metal CP, and multi-metal CP. Owing to particular coordination characteristics arising from 4f electrons,lanthanide CPs(Ln-CPs) has unique optical, electrical and magnetic properties as an important class of the CP family. The transition metal CP whose coordination number is usually 4 or 6 is different from rare earth metal in light, electricity and gas adsorption performance. So double metal CP made up of rare earth metal and transition metal may have unexpected structures and properties. Furthermore, all sorts of metal oxides, metal sulfides, oxysulfides, oxysulfates and other inorganic materials can be successfully obtained from the above precursors by simple thermal processing.It has been demonstrated that inorganic materials derived from CPs precursors possess more useful properties. In this paper, several organic small molecules owing carboxyl and sulfydryl are considered as the linkers, we have reported a facile hydrothermal and solvothermal method to synthesize the rare-earth and multi-metal micro/nanostructures. Then, the obtained products were calcined under the nitrogen or oxygen atmosphere. Finally, a variety of characterization methods are used to study the structure and properties of products.The main content of this paper is as following:(1) Thermolysis preparation of Re2O2SO4 microspheres from rare earth-based coordination polymersRare earth-based coordination polymers(Re-CPs) spheres have been prepared by using meso-2, 3-dimercaptosuccinic acid(DMSA) as ligand and deionized water(H2O) as solvent under hydrothermal condition. Re2O2SO4 microspheres with similar morphology and diameters of 1-2 ?m were prepared through a subsequent calcination of the corresponding Re-CPs in the air at 700 °C for 4 h. However, CeO2 microspheres and Sc2O3 nanoparticles were obtained after calcining their corresponding CPs. The products were characterized using X-ray diffraction(XRD)and scanning electron microscopy(SEM). Thermogravimetric analysis(TG), infrared spectroscopy(IR), laser Raman spectrometry(Raman), energy dispersive X-ray spectrum(EDX), Elemental analysis(EA) and inductive coupled plasma(ICP) atomicemission spectrometer were adopted to study the composition of the europium-based coordination polymers(Eu-CP). To explore their potential applications, several samples of the products were selected and their properties were investigated. For example, the Eu-CP and Eu2O2SO4 microspheres show strong red emissions under 394 nm ultraviolet excitation, the Eu-CP displays a highly selectivity for Fe(III). The obtained CeO2 has a strong absorption in the UV region and big forbidden gap. The Gd2O2SO4 shows paramagnetic behavior.(2) Multi-metal of europium and cadmium coordination polymer nanoparticles:preparation and their conversion to Eu2O2S/CdS heterostructureA multi-metal CP nanoparticles with diameters of 20-40 nm have been successfully prepared by employing Eu3+ and Cd2+ as central metal ions and meso-2,3-dimercaptosuccinic acid(DMSA) as ligand under hydrothermal method at lower temperature. We got the Eu2O2S/CdS heterostructured material through a high-temperature treatment of the as-prepared coordination polymer under the N2 atmosphere. The influence of calcination temperature on the synthesis of product was investigated in detail. Results show that the temperature is the critical factor to prepare heterojunction materials. The as-prepared products were characterized using different methods. In addition, the luminescent property of europium-cadmium coordination polymer was also studied. The method is expected to expand to synthesis of other heterostructure materials.(3) Multi-metal of cerium and cadmium coordination polymer nanospheres:preparation and their conversion to CeO2/CdS heterostructureMulti-metal of cerium and cadmium CP nanospheres which were based on mixed ligands(L-cysteine and terephthalic acid), mixed solvents(H2O and DMF) and mixed metal ions(Ce3+ and Cd2+) were fabricated via a solvothermal precess. It is generally known that morphology and crystallinity of the final product depend on the reaction environment. In order to better find the optimal experiment conditions, a series of controlled experiments were performed to carefully study the morphological evolution.Therefore, the molar ratio of reactants, the reaction temperature and the reaction time should be taken into account. What's more, the typical sample was placed in nitrogen atmosphere for high temperature calcination. Results show that the calcined products are CeO2/CdS heterostructured nanospheres.