| Polyoxometalates?POMs?stand for a large class of discrete metal-oxo anions of early transition matals such as V,Nb,Mo,W.Its rich structure and intriguing physical and chemical properties of POMs make it exhibit many potential applications in the fields of catalysis,proton conduction,magnetism,biomedicine and nanomaterials.In recent years,the polyoxometalate-based inorganic-organic hybrid materials by using polyoxometalates as a building block are a hot field in the research of polyoxometalate-chemistry through utilizing the modification of polyoxometalates.Since the polyoxometalate-based inorganic organic hybrid materials combine the advantages of polyoxometalates and functional ligands,they are good candidates for designing and synthesizing functional materials with novel structures and superior performance.In this paper,combined with the problems in the development and application of polyacid-based hybrid materials,polyoxometalates as inorganic ligands or templating agents can be coordinated with transition metal ions by selecting different nitrogen heterocyclic ligands from the perspective of structural design.By continuously improving the reaction conditions,fifteen novel polyoxometalate-based inorganic organic hybrid materials were obtained,and the structural composition and functional properties of the compounds 1?15 were explored and studied.The compounds were characterized by infrared spectroscopy,X-ray powder diffraction,and thermogravimetric analysis.The magnetic,photocatalytic,proton,and electrochemical catalysis of some inorganic and organic hybrid materials were measured.The main research contents and results in this thesis are as follows:?1?Four isomorphous polyoxometalate-based inorganic organic hybrid materials were obtained by the self-assembly of 2,6-bis?1,2,4-triazol-1-yl?pyridine?btp?ligands,Mn?II?/Fe?II?/Co?II?/Zn?II?ions and Dawson-polyoxometalate anions:[M3?btp?3?H2O?12](?-P2W18O62)?btp?3·18H2O?M=Mn?1?,Fe?2?,Co?3?,Zn?4??.In compounds 1?4,the three transition metal ions are formed a metal organic ring{M3L3}with three btp ligands.The upper and lower sides of the Dawson polyacid anion[?-P2W18O62]6?are firmly anchored by hydrogen bonding interaction,and the surrounding sides are tightly surrounded by the?...?stacking interaction between the btp ligands.The staggered metal organic rings{M3L3}and the free btp ligands are formed a 3D framework structure through?...?stacking and hydrogen bonding interaction.Interestingly,the size of 1D channel is the of 15?×15?in the 3D structure.The coordinating water molecules are exposed in the 1D channels,and a large amount of water molecules are free in the 1D channels.It is worth mentioning that this kind of compounds can remain structurally stable in acidic,neutral,even alkaline.Because of their strong stability,at 20°C and relative humidity of 100%,the proton conductivity of compound 1 was measured,which is 1.26×10?5 S cm?1,showing good proton conductivity.Compounds 1?4 exhibit antiferromagnetic behaviors and exhibited certain photocatalytic degradation effect on Rhodamine B organic dye.Compound 2 also exhibits good electrochemical activity for the reduction of H2O2.?2?Fourisomorphouscompoundswereobtainedbytheself-assembly 2,6-bis?1,2,4-triazol-1-yl?pyridine?btp?ligands,Co?II?/Zn?II?/Cd?II?/Mn?II?ions and Keggin-polyacid anions:{[M2?btp?3?H2O?6](?-SiW12O40)·3H2O}n?M=Co?5?,Zn?6?,Cd?7?,Mn?8??.In compounds 5?8,the metal ions are coordinated with the btp ligands to form 2D layers,and the polyacid anions[?-SiW12O40]4?exist in the adjacent layers by electrostatic interaction to form a 3D sandwich framework structure.Compound 5 not only exhibits good electrochemical activity for the reduction of H2O2 but also exhibits good photocatalytic activity for Rhodamine B organic dye.Magnetic data indicates that the compounds 5and 8 exhibit antiferromagnetic behaviors.Compounds 5?8 also feature non-linear optics behavior.?3?Based on 2,6-bis?1,2,4-triazol-1-yl?pyridine?btp?,1,4-bis?1-imidazolium?benzene?bib?, 2,6-dis?1-imidazole?pyridine?2,6-bip?,3,5-di?1-imidazolium?pyridine?3,5-bip?,seven polyoxometalate-based inorganic organic hybrid materials were obtained by the self-assembly of polyacid anionsandtransitionmetalions:?9?,{[Ni?2,6-bip?2?H2O?(H4W12O40)0.5]·H2O}n {[Co?2,6-bip?2?H2O?(H4W12O40)0.5]·H2O}n{[Zn3?bib?6(H3ZnW12O40)2]·14H2O}n ?10?,?11?,{[Ni2?bib?2?H2O?2(H4W12O40)]?bib??7H2O}n?12?,?13?,{[Ni?3,5-bip??H2O?2(?-Mo8O26)0.5]·3H2O}n [Ni2?btp?2(H4Mo6O22)]n?14?,{[Co2?btp?2?H2O?4(Mo8O26)]·6H2O}n?15?.Compounds 9 and 10 are isomorphous,the[H4W12O40]4?polyacid anions are coordinated with metal ions to form 1D chains,which are stacked to a novel 3D framework structure by the?...?stacking process.In compound 11,polyacid anions[H4W12O40]4?are interacted with metal ions to form a 2D layered structure,and the 2D layers are further extended to 3D sandwich structures by the connection of bib ligands.In compound 12,the Zn?II?ion are coordinated with the terminal oxygen atoms of the polyacid anions[H3ZnW12O40]3?and the nitrogen atoms on both sides of the bib ligands to from 1D chains.Through the?...?stacking interaction force between the bib ligands,1D chains are formed 2D layer and 3D structure.In compound 13,Ni?II?ions are coordinated with the organic ligands form 2D layers,and[?-Mo8O26]4?polyacid anions exist the adjacent layers by electrostatic interaction to form a 3D framework.In compound 14,Ni?II?ions are interacted with polyacid anions[H4Mo6O22]4?and btp ligands to extend 2D layers,and the 2D layers formed 3D framework structures by?...?stacking between bpt ligands.In compound 15,the Co?II?ions are alternated connection with the polyacid anions[Mo8O26]4?to form 3D framework,and the btp ligands are fromed a novel 3D framework structure by joining adjacent two Co?II?in the 3D Organic framework.Furthermore,the electrochemical properties of the compounds 9,10,14 and 15 are investigated,the compound 15 exhibits good electrochemical activity for the reduction of NaNO2.Magnetic data indicates that the compounds 9,10 and 15 exhibit antiferromagnetic behaviors.Compound 10 exhibits good photocatalytic degradation activity to the Rhodamine B. |
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