Syntheses, Structures And Properties Of Tungsten-containing Polyoxometalate Cluster

On the basis of molecular design and assembly, the polyoxometalate compounds supported by isopolyanions as building blocks were successfully synthesized by the ambient-temperature aqueous solution (or mixed solvent) and water-bath refluxing methods, which are"decorated"or"bridged"by organic N-donor and/or O-donor ligands. The study on synthetic conditions and characterization by X-ray crystallography, spectroscopic, thermal, electrochemical and magnetic properties. (I) Four novel similar planary Keggin-type compounds supported by isopolytungstate were obtained by reaction of Na₂WO₄·2H₂O, 4,4'-bipy, 1, 10-phenanthroline or EDTA and MCln·nH₂O (M= Co, Cu, Ni)under controlling the acidity of solution. These compounds are characterized by IR, UV, ICP analyses, element analysis, TG-DTA, Electrochemical measurements and single crystal X-ray diffraction analysis. (II) An unprecedented Keggin-type tungstogermanate dimer bearing dinuclear copper-organic coordination ions {H₈[Cu(phen)(μ2-CH₃COO)₂Cu(phen)(H₂O)]₂ [Ge₂W₂₃CuO₈₀]}·24H₂O has been synthesized by reaction of Na₂WO₄·2H₂O, GeO₂, CuCl₂·2H₂O, 10-phenanthroline and so on and characterized by IR, UV, ICP analyses, ESR spectra, element analysis, TG and single crystal X-ray diffraction analysis. (III) Two transition-metal Sandwich-type compounds were synthesized by reaction of Na₂WO₄·2H₂O, GeO₂, MCl₂·nH₂O (M = Co, Cu). These compounds are characterized with spectroscopic, thermal properties and X-ray crystallographic studies.