Synthesis And Characterization Of Inorganic-organic Hybrid Compounds Based On Polyoxometalates

Polyoxometalates (POMs) as a unique class of metal-oxide clusters exhibit structuraldiversity. Because of the structural features and good properties, they have been applied incatalysis, magnetism, porous materials, medicine research, biology, photochemistry and soon. Because of its rich negative charges, it could be an important inorganic building block.POMs could be modified with metal-organic complexes and organic fragments, whichwould yield new inorganic-organic hybrid compounds with new constructions and improvethe property of POMs.In the work, Keggin POMs are used as basic building blocks and phen,4,4′-bipy andproline as organic ligands, and five different inorganic–organic hybrid compounds aresynthesized. They are characterized by single-crystal X-ray diffraction analyses, IR,elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Byparallel experiments, the optimal reaction conditions are founded and pH value, reactiontime and temperature are quite important for the synthesis of the hybrids. The UV-visspectra, fluorescence properties, and electrochemical properties of the five compounds areresearched.1. The synthesis of three inorganic–organic hybrid compounds based on Keggin POMsand mixed ligands.Three different inorganic–organic hybrid compounds based on keggin typepolyoxometalates (POMs), namely,[CuII2(phen)2(4,4′-bipy)(H4,4′-bipy)2(H2O)2][PMo12O40]2·2H2O (1),[CuII(phen)2(H4,4′-bipy)][PW12O40]·H2O (2),[CuII2(phen)2(4,4′-bipy)(BW12O40)(H2O)2](H24,4′-bipy)0.5·3H2O (3)(phen=1,10-phenanthroline,4,4′-bipy=4,4′-bipyridine), were synthesized by changing the POMsin the hydrothermal conditions. Compounds1-3were characterized by single-crystal X-raydiffraction analyses, IR, elemental analyses, powder X-ray diffraction analyses, andthermogravimetric analyses.2. The assembly of inorganic–organic hybrid compounds based on Keggin BW12andcobalt(Ⅱ) ions.Two various hybrids based on Keggin BW12anions were synthesized, which were[CoII3(proline)2(4,4′-bipy)2(H4,4′-bipy)4(OH)2(H2O)4][BW12O40]2·6H2O (4) and [CoII2(proline)(4,4′-bipy)(H4,4′-bipy)2(OH)(H2O)2][BW12O40]·3H2O (5). They arecharacterized by X-ray single crystal diffraction, FT-IR spectra, X-ray powder diffraction,element analyses and TG analyses and XPS spectra.