Synthesis,Structure,Characterization And Properties Of Novel Polyoxotungstates

Polyoxotungstates(POTs)has an increasingly important application in catalysis,magnetism,fluorescence,electrochemistry and biological activity due to its rich construction unit and excellent physical and chemical properties.This paper has synthesized 11 new organic-inorganic hybrid POTs by hydrothermal synthesis method.The structure and properties of compounds were studied by X-ray powder diffraction(PXRD),Fourier transform infrared spectrum(FT-IR)and two-dimensional infrared correlation spectroscopy(2D-IR COS),UV-vis solid diffuse(UV-vis DRS),Thermogravimetric analysis(TGA)and steady-state fluorescence spectrum analysis(FL)The main contents and innovations are as follows:(1)Lanthanide metals were introduced in the trivacance-precursors and obtained 4 Ln-monsubstituted Keggin type polyoxosilicotungstates(compound 1-4).The one-dimensional structure of 1-4 is connected by the Ln-O bond.The Ln ions are all eight coordination mode while the coordination methods are variant.So the similarities and differences of the four compounds are discussed in detail from the structural aspect.It can be seen from the analysis of variable temperature magnetic susceptibility that compounds 2 was antiferromagnetic interaction and 3 was paramagnetism.The experimental results of the biobacteriostatic activity of two kinds of fish spoilage bacteria showed that compound 1 was an effective antibacterial material.This in the first work to inhibit the growth of fish spoilage with POTs.(2)Introduced organic aromatic ring molecules(2,2-bipy/pyrimidine)to constructed POTs and obtained compound 5-8,which the central atom is V,O,P,and Si respectively while the transition metal is Ag+?Cu2+ and Mn2+ respectively.What's more,5-8 are zero dimensional structure and there existed abundant ?-? packing between molecules.What is noteworthy is that the structure of compound 7 is the first,which a position of W atom was replaced by two Cu atom that approximately parallelly arrayed.Interestingly,the raw reactant pyrimidine was in situ reaction and produced hyamine.This reaction in POM is the first.and 8 has reversible photochromic effect.(3)Introduced flexible small-molecule amine(en/1,2-dap)to constructed polyoxosilicotungstates and botained compound 9-11.Among them,9 is one-dimensional single-chain structure,10 is one-dimensional double-chain structure,and 11 is a zero-dimensional structure with three direction spiral chains.It can be seen from the analysis of variable temperature magnetic susceptibility that compounds 10 was antiferromagnetic interaction and 3 was paramagnetism Compound 11 and organic dye RhB can form complex compounds and the association ratio of crysta-dye complex is explored.