| Polyoxometalates (POMs) are an attractive molecular clusters not only because of their unlimited structural versatilities and appealing structural features, but also due to their rich electrical and optical properties, one of which is their electron donor-acceptor capability which makes POMs excellent candidates as "electron".These kinds of decorated polyoxometalate derivatives can be regarded as an ideal atomic level structural model for the determination of the mechanisms of oxide-supported catalysts. Furthermore, such kinds of compounds can be fine-tuned in molecular level and provide potentially new types of catalyst systems as well as interesting functional materials with optical, electronic and magnetic properties.In this thesis, four novel heteropolyoxometalate compounds containing transition metal-organic complex were synthesized and characterized by X-ray crystallography, IR and TG . their chemical formulas are listed as follows:(1)[H3PMo8V6O46][Ni(en)2]·2[Ni(en)2]·5H2O(2) {PMo8V6O42[Cu(1)(en)2]·[Cu(2)(en)2]0.5·[Cu(4)(en)2]0.5·[Cu(5)(en)2]0.5}- [Cu(3) (en)2]·6H2O(3)[Mn2Mo12O30(HPO4)8(H2O)]-(NH3CH2CH2NH3)6·3.5H2O(4) [P2W18O62]·[Fe(C10H8N2)3]2·12H2OX-ray crystallography analysis show that the polyoxometalate anion cluster with bicapped 'pseudo-Keggin' structure bound to transition metal Ni/Cu-organic complex in compound (1) and compound (2). Compound (3) exhibit a sandwich-like heteropoly molybdomanganesophosphate with Mn(II) as central atoms. There exists strong intermolecular interaction between the Dawson structure type polyoxometalate anion and organic donors in the compound (4).The compound (1) and (2) exhibit high activity in the selective oxidation of benzyl alcohol to benzaldehyde and the dehydration of cyclohexanol. Effect of catalyst amount, H2O2/ C6H5CH2OH (volume ratio), reaction time and reusable times on the catalytic activity were studied.The nanoparticles of polyoxometate H4[PMo11VO40]·28H2O and were synthesized and characterized. |
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