نتایج جستجو برای: keggin
تعداد نتایج: 480 فیلتر نتایج به سال:
Original and effective syntheses of crystalline silver wires and saw bundles, using reduced Keggin polyoxomolybdovanadate (POM) as mediator and reducing agent, were performed in acetonitrile at room temperature; several parameters influencing the final silver 1D-structures, with micrometric length and nanometric thickness, were varied: the nature of the POM, silver salts, vanadium(iv) source an...
Immobilization of the chiral salen-metal complex [Mn(III)(salen)(H(2)O)(2)ClO(4)] on the Keggin-type polyoxometalate (POM) skeletons leads to the isolation of POM derivatives functionalized with chiral salen-metal complexes, which represent the first examples of introducing chiral salen-metal complexes into the POM systems.
The reaction of a saddle-distorted Mo(v)-dodecaphenylporphyrin complex and a Keggin-type polyoxometalate gives a discrete and nanosized molecule, [{Mo(DPP)(O)}(2)(H(2)SiW(12)O(40))], which involves direct coordination between the Mo(v) centers and terminal oxo groups of the polyoxometalate and exhibits excellent stability in solution to show reversible multi-redox processes.
A correlation between polyoxotungstate structures and their catalytic performance for oxidative desulfurization processes was investigated. Bridged lanthanopolyoxometalates that incorporate identical metallic centers with Keggin- Eu[PW11O39]11? Lindqvist-type [Eu(W5O18)2]9? were used as catalysts the oxidation of most representative refractory sulfur compounds. Both compounds able to desulfuriz...
Keggin-type heteropolyacid cesium salts have been regarded as potential candidates for heterogeneous catalytic reactions. This review describes the success of heteropolyacids (Cs-HPA salts) efficient catalysts in various synthesis processes. The Cs-HPA can be synthesized solid through metathesis a solution containing precursor HPA and another soluble Cs salt, which will give salt precipitate. A...
Keggin heteropolyacids (HPAs) are metal–oxygen clusters with strong Bronsted acidity. The conversion of HPAs to metal salts can result in Lewis acidity, improving their performance oxidation reactions. In this review, the main routes for synthesis Keggin-type salts, as well use catalysts processes a plethora substrates, such monoterpenes, olefins, aldehydes, terpene alcohols, and aromatics, des...
H [PV Mo O ] catalyzed oxidation of thiols to related disulfides under microwave irradiation(MW). 5 2 10 40 Hydrogen Peroxide as an oxidizing reagent under mild conditions carried out this reaction. This system provides an efficient convenient and practical method for the syntheses of symmetrical disulfides. In this work, the comparisons among the Keggin and Dawson type polyoxometalates are add...
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