Syntheses And Properties Of New Polyoxometalates Based On Tungstate Building Units

The aim of this thesis is the synthesis of new polyoxotungstates on the basis of sodium tungstate by exploiting metal cations and organic ligands. The study on synthetic conditions and rules for these new compounds and the exploration of relationships between structures and properties for these new compounds are also carried out.Six new polyoxotungstates compounds have been synthesized by making use of hydrothermal technique synthesis methods and structurally characterized by elemental analyses, IR, XPRD, TG, XPS and single crystal X-ray diffractions.The thermal stabilities, electrochemical properties and fluorescent activity of these compounds have been studied.1. Two polyoxotungstates compounds have been synthesized on the basis of Keggin and Dawson-like type polyoxoanion cluster which are liked with Cu-Ligand:[Cu(en)₂][Cu(en)₂(H₂O)][Cu(en)(phen)][CuW₁₂O₄₀]·3H₂O (1)[Cu(phen)(H₂O)]₂[Cu(phen)(H₂O)₃]₂H[SbW₁₈O₆₀]·5H₂O (2)Compound 1 contains classic Cu-centered Keggin-type and links with [Cu(phen)(en)]2+ to form 1D helical chain. Compound 2 is an unusual Dawson-like type polyoxotungstate.2. Two supramolecular compounds have been hydrothermally synthesized on the basis of Co-centered Keggin-type polyoxotungstate: (H₂bpe)₃[CoW₁₂O₄₀] (3)[Co(mbpy)₃]₂H₂[CoW₁₂O₄₀]·2H₂O (4)Compound 3 is 2D supramolecular compound via hydrogen bond interactions andπ···πinteractions. Compound 4 is supramolecular compound only via hydrogen bond interactions.3. Two new compounds with extended structure have been prepared by using different polyoxometalates as building blocks and introducing Cu-bpe coordination polymeric chains: [Cu(bpe)]₆ [HCu_0.5W₁₂O₄₀]·6H₂O (5)[Cu(bpe)]₆[PWV₃WV₁₉O₄₀]·8H₂O (6)Compound 5 is 3D extended structure, while the adjacent layers of compound 6 are linked up together to form 3D network throughπ···πinteractions.