Hydrothermal Synthesis, Structure Characterization And Properties Of Polyoxometalates Decorated And Linked By Transition Metal Copper-Organonitrogen

On the basis of molecular design and assembly, the aim of synthesizing new polyoxometalate compounds on the saturated Keggin-type and Dawson-type polyoxoanion clusters, which are decorated or bridged by various copper - organonitrogen compounds. The study on synthetic conditions and rules for these new compounds are carried out. Six novel polyoxometalates have been hydrothermally synthesized and structurally characterized by the single-crystal X-ray diffraction analysis,IR spectroscopy and TG analysis.1.Five new polyoxometalate compounds on the basis of saturated Keggin-type polyoxoanion cluster have been hydrothermally synthesized and structurally characterized:Compound 1 and 2 are copper-organonitrogen polyoxometates Keggin [BW₁₂O₄₀]^5- polyanion as building block. The most remarkable structural feature of Compound 2 is that it has a [BW₁₂O₄₀Cu(2,2'-bipy)₂(H₂O)Na_0.5]^3- polyanion. Compound 3 shows a 2-D layer framework constructed from bisupporting Keggin polyoxoanion clusters and [Cu(2,2'-bipy)₂]²⁺ coordination polymer fragments via weak covalent interactions, resulting in a 3-D network via supramolecular interactions. Compound 4 is a novel [BW₁₂O₄₀]^5- polyoxoanion which is bisupported by copper(â… ) coordination cations with mixed 2,2'-bpy and 4,4'-bipy ligands. Compound 5 exhibits multidimensional structures formed by Keggin-type polyoxoanion and copper-organonitrogen compounds with mixed 2,2'-bipy and 4,4'-bipy ligands.2. One new polyoxometalate compound which is on the basis of saturated Dawson-type polyoxoanion cluster has been hydrothermally synthesized and structurally characterized:Compound 6 is built up of [P₂W₁₈O₆₂]^6- cluster as the structural motif covalently linked by [Cu(2,2'-bipy)₂]²⁺ coordination complexes to yield the 1-D chains, which are further in close contact forming a 3-D supramolecular framework via aromaticÏ€-Ï€stacking interactions and extensive hydrogen-bonding interactions among polyoxoanions, coordinated 2,2'-bipy organic ligands, free dpdo organic molecules and lattice water molecules.