Synthesis And Properties Of Hybrid Materials Based On Keggin-type Polyoxometalates

Polyoxometalates (POMs) are a unique class of inorganic metal-oxygen aggregates with unmatched molecular structural diversity and versatile chemical, physical and biological properties. The oxygen-rich surface makes POMs be excellent building blocks to connect with diverse metal nodes for the formation of a variety of functional materials with interesting properties for potential applications in a number of fields, such as catalysis, medicine, electronics, materials science and optics.In this thesis, I used the Keggin-type POMs as the building blocks with transitional metal cations, lanthanide cations and organic ligands as linkers to construct a series of POMs-based compounds with three-dimensional structures. The crystal structures and properties of these compounds were sufficiently characterized.(1) Ten isostructural compounds1-10with three-dimensional diamondoid structures were constructed from{ZnW12O40} or{CoW12O40} connected by lanthanide cations. These compounds were characterized by single crystal X-ray diffraction, IR, TGA and PXRD. The luminescence of compounds1-3was studied.(2) Three isostructural porous organic-inorganic hybrids11-13with three-dimensional structures were constructed with{ZnW12O40} and tetrapyridylporphyrin (TPyP) connected by transitional metal cations. These compounds were characterized by single crystal X-ray diffraction, IR, TGA and PXRD.(3) A1D anionic polyoxometalate compound14constructed from [WZn{Mn(H2O)}2(ZnW9O34)2]12-and Mn2+underwent1D to3D single-crystal-to-single-crystal structural transformations that were induced by transition-metal cations (Co2+, Cu2+) and solvent molecules. This work provided a new pathway for the synthesis of high-dimensional solid POMs.