| In this thesis,four new polyoxometalates?POMS?compounds were synthesized by selecting 3-aminopyrazine-2-carboxylic acid?apca?and 4,4-bipyridine?bipy?,which are common ligands.The above compounds were characterized by single crystal X-ray diffraction,X-ray powder diffraction,fluorescence spectrum,infrared spectrum,thermogravimetric analysis and element analysis.Based on the properties of ligands and metal ions,and the analysis of the structure,the proton conductivity and photoluminescence properties of the compounds were investigated,which provided a basis and reference for the exploration of proton conductive materials and luminescent materials.1.Synthesis of two new Keggin supramolecular compounds[Cr?apca?2?H2O?2]4[KBW12O40]·9H2O?1?[Al?apca?2?H2O?2]8[SiW12O40]2·13H2O?2?Compounds 1 and 2 were synthesized in conventional aqueous solution and characterized by single crystal X-ray diffraction,elemental analysis,thermogravimetric analysis,X-ray powder diffraction,infrared spectrum and fluorescence spectrum.In compound 1 the[BW12O40]5-anion acting as octadentate ligand coordinates to two K ions through weak interaction,forming an infinite anionic chain extending along c–axis.The chains locate in the channels formed by stacking of the complex cations[M?apca?2?H2O?2]+.Hydrogen bonds combine the chains,cations and lattice water molecules forming a 3D structure.Besides the hydrogen bonds there exists?*-?interaction between the complex cations.Compound 2 has a similar structure except without the K+ion.They show a high proton conductivity of 1.70×10-3S cm-11 and 9.30×10-33 S cm-11 at 77°C under 97%RH,respectively.Compound 1-2showed reversible skeleton structure changes upon dehydration and rehydration,which had been established and monitored by X-ray powder diffraction.2.Synthesis of two sandwich-type lanthanide-modified polyoxometalates compounds?H2bipy?2[Nd??-PW11O39??H2O?3]·5H2O?3??H3O?2?H2bipy?10[Ce??-PW11O39?2]·0.25?bipy?·11.5H2O?4?The lanthanide-decorated polyoxometalates[Nd(?-PW11O39)?H2O?3]?H2bipy?2·5H2O?3?and[Ce(?-PW11O39)2]·2?H3O?·10?H2bipy?·0.25?bipy?·11.5H2O?4?were obtained under hydrothermal conditions.(?-PW11O39)n-coordinates with lanthanides in different coordination ways in compounds 3 and 4,so there are some differences in structure.Compound 3 exhibits three characteristic emission peaks with high emission intensity and is expected to be used as a luminescent materials.Compounds 3-4 show low proton conductivity of 2.70×10-77 S cm-11 and 2.20×10-77 S cm-11 at 77°C under97%RH,respectively. |
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