Synthesis, Crystal Structure And Properties Research Of Keggin-Type Polyoxometalate Based On Tungstate Anions

Under hydrothermal condition, Keggin-tpye polyoxometalates as the the building blocks, five novel organic-inorganic hybrid compound have been synthesized based on polyoxometalates (POMs) modified by transition-metal complex cations.The chemical formulas of five compounds have been determined by elemental analyses and TG analysis: [Cu(bpp)][Cu2.5(bpp)3(Hbpp)]H0.5[BW12O40]·1.5H2O(1) [Cu(en)2(H2O)]{[Cu(bpp)]3[AlW12O40]}·H2O(2) Na[Na(Hchtpy)](Hcbhtpy)[NaAlW12O40](3) [Co(Hbztpy)(H2bztpy)][AlW12O40]}·H2O (4) [Cu(en)2][{Cu(en)2}2PNaW11O39]·0.5H2O(5)The new compounds are structurally characterized by single crystal X-ray diffractions and IR. For compound 1, as the nodes, the [BW12O40]5- polyanions link to the [Cu2.5(bpp)3(Hbpp)]3.5+ oligomers, leading to the formation of 1D helical chains which further attach to the macrocycles [Cu2(bpp)2]2+ via the Cu-0 weak interaction to construct the 2D "wave-like" layers. For compound 2, the{[Cu(bpp)]4[AlW12O40]2} units are sandwiched by two 1D "wave-like" polymeric chains resulting in a new ID structure. The{[Cu(bpp)]4[AlW12O40]2} unit is obtained by the interaction between two Keggin-type [AlWi2O40]5- polyanions and one tetranuclear macrocycle composed by four [Cu(bpp)]+ complex cations. Compound 3 and 4 are based on [AlW12O40]5-polyanions as the building blocks. In compound 3, the 1D chain is constructed by Na ions linking to polyanions, swimming by the in-suit ligands chtpy and cbhtpy, the central structure of which is hexamethylene, while chtpy coordinating with another Na ion. In compound 4, Co ions link to in-suit ligands benzene-centered bztpy to form the 1D chain, synchronously connect with the Keggin-type polyanions to obtain the 3D framework with nano-pore structure. In compound 5, the 1D chains, which are constructed by Na cations linking to the lacunary Keggin-type polyanions. are connected by [Cu(en)2]2+ complex cations to form 3D framework.The study of electrochemical properties of the compound 1,2,3 and 5 indicated that all of them had the redox property. Additionally, compound 5 was found the ferromagnetic interaction.