Synthesis And Catalytic Oxidation Of H₂O To O₂of New Complexes Based On Trilvacant And Saturated Keggin-heteropolytungstates

In this thesis, four complexes based on trilvacant and saturated Keggin-heteropolytungstates have been synthesized under hydrothermal and normal temperatureconditions, and characterized by X-ray single crystal diffraction, elemental analysis, IR andTG. Some of them have been studied for the catalytic oxidation of H2O to O2.1. Two complexes based on Trilvacant Keggin-polyoxotungstates and Co2+have beensynthesized based on normal temperature conditions:Na₉H₅[Co₂Bi₂(α-B-CoW₉O₃₄)₂]·58H₂O1Na₁₄[Co₂Bi₂(β-B-CoW9O₃₄)₂]·48H₂O21and2are isomers, they consist of two [Co₂Bi₂(α or β-B-CoW₉O₃₄)₂]^14--subunits linked by twooctahedron [CoO₆] and two distorted pentagonal pyramid [BiO₅]. The four Co2+in the anioncan be divided into two different structural types: Co1which plays the role of a primaryheteroatom is fore-coordinated by four O atoms in the center of each trilacunary (α or β-B-CoW₉O₃₄)^9--ligand, Co₂is six-coordinated by six O atoms which links two(α or β-B-CoW₉O₃₄)^9--units along with two Bi3+.2. Two complexes based on Keggin-polyoxotungstates anions,4,4’-bipy and Cu²⁺havebeen synthesized hydrothermally:{[Cu（4,4’-bipy）_3/2（OH）（H₂O）]₂[H₂GeW₁₂O₄₀]}·4H₂O3{[Cu（4,4’-Hbipy）₄]₂}{[SiW₁₂O₄₀]₃}（4,4’-bipy）·5H₂O4The structure of3can be considered as an1D infinite zigzag chain built up throughbridging Cu²⁺ions with OH-and4,4’-bipy. The chains are linked via [XW₁₂O₄₀]^4-（X=Si/Ge）anions into a2D layered structure. Viewed along the b axis, the distance between the layers is4.9. The chains are linked into a2D layered structure via [SiW12O40]4-anions. The2Dlayers are stacked together along the b axis, forming channels with the approximatedimensions of15.6×13.3. In4, an1D infinite zigzag chain constructed from [SiW₁₂O₄₀]^4-and metal organic fragment. The chains are bridged via OH-groups O36–H–N7（2.896） intoa2D layered structure.3. The photocatalytic and electrocatalytic oxidation of H₂O to O₂have been studied for1and2. They exhibit the photocatalytic activity and electrocatalytic for O₂evolution. AverageO2evolution rates are0.253μmol/min and0.469μmol/min, respectively.