Design,Synthesis And Properties Of Novel Polyoxovanadates

Polyoxometalate（POVs）are an integral component of polyoxometalate（POMs）.Vanadium has variable oxidation states（III,IV,V）,can form reduced or mixed valence POVs,its multiplicity of co-ordinations allows for the construction of different geometries（tetrahedral,tetragonal,triangular bipyramidal and octahedral,etc.）.POVs have good redox,catalytic and biomedical properties and have attracted a lot of attention from researchers in recent years.In this thesis,seven heteropolyvanadates were obtained by solvothermalmethod,using VOSO₄as raw material,phenylphosphonic acid as organic ligand,adding different inorganic metal salts to introduce tungsten,molybdenum,bismuth and other heteroatoms into the POVs system to construct heteropolyvanadates.Their catalytic oxidative desulfurization,iodine and dye adsorption properties were explored.This thesis can be divided into the following three parts:（1）Based on our group’s preceding studies,three high-nuclear heteropoly tungstovanadates（compound 1-3）were synthesized by using a new pentagonal{WV₅（Ph PO₃）₅}MBB.Three different arrangements of the pentagonal{WV₅（Ph PO₃）₅}building blocks can be observed,including face-to-face,corner-to-corner and forming dimers{V₁₀W₂（Ph PO₃）₈}.Compound 1 showed efficient,stable and versatile catalytic activity for sulfur oxidation.（C₂N₁H₈）₆[Na₁₀(V₂₀W₂O₃₂)（Ph PO₃）₂₀（SO₄）₂]·4DMA·6CH₃OH（1）（C₂N₁H₈）₉[Na₇(V₁₈W₄O₃₈)（Ph PO₃）₁₄（ox）₄]·4DMF·10CH₃OH（2）（C₂N₁H₈）₁₀[Na₁₀（ox）₂（H₂O）₆（DMF）₂(V₂₆W₆O₆₂)（Ph PO₃）₁₆（DMF）₂]·4DMF·11CH₃OH（3）（2）A heteropolytungstomolybdovanadate（compound 4）was synthesized using the solvothermalmethod,compounds 5 and 6 were also obtained under the same circumstances.Compound 4 also has a pentagonal{WV₅（Ph PO₃）₅}building block,and compounds 4-6 all have a{Mo₂O₁₀}building block,which is a common building block in the{Mo₁₃₂}structure.Compound 4 was studied for iodine adsorption and was found to have good adsorption of iodine molecules.（C₂N₁H₈）₇[V₁₆Mo₁₀W₂O₅₈（Ph PO₃）₁₈（Ac）₂]·9CH₃OH（4）（C₂N₁H₈）₃[V₁₆Mo₁₀O₅₀（Ph PO₃）₈（ox）₁（SO₄）₂]·6CH₃OH（5）（C₂N₁H₈）₄[V₁₀Mo₄O₂₀（Ph PO₃）₁₂（ox）₃]·5CH₃OH（6）（3）The bismuth-based vanadate（compound 7）was prepared by introducing bismuth into POVs under solvent-heated conditions.Compound 7 contains two tetranuclear bismuth clusters{Bi₄P₅O₂₂},which is similar to the structure of Bi₄O₂（OAr）₈previously reported by Hanna’s group.Compound 7 was studied for dye adsorption and we found that it could selectively adsorb cationic dyes.（C₂N₁H₈）₇[V₁₆Bi₈O₃₆（Ph PO₃）₁₄（SO₄）₁]·10CH₃OH（7）...