نتایج جستجو برای: keggin
تعداد نتایج: 480 فیلتر نتایج به سال:
We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwa...
Summary The term self-assembly is used to describe the formation of many molecules and supramolecular architectures, but often, precise mechanism neglected. Here, we have investigated kinetics simplest heteropolyoxoanion, Keggin ion [XMo12O40]x–. This study variable temperature UV/vis spectroscopy show that can catalyze its own via an autocatalytic cycl...
About 240,000 square kilometers of Earth's surface is disrupted by mining, which creates watersheds that are polluted by acidity, aluminum, and heavy metals. Mixing of acidic effluent from old mines and acidic soils into waters with a higher pH causes precipitation of amorphous aluminum oxyhydroxide flocs that move in streams as suspended solids and transport adsorbed contaminants. On the basis...
The title polyoxometalate-based organic-inorganic hybrid compound, (C(5)H(10)NO(2))(5)[BW(12)O(40)]·3H(2)O, consists of one α-Keggin-type [BW(12)O(40)](5-) polyoxoanion, five crystallographically independent l-prolinium cations and three uncoordin-ated water mol-ecules. The polyoxoanion shows characteristic features with respect to bond lengths and angles. Several N-H⋯O and O-H⋯O hydrogen bonds...
Epoxides are an important class of industrial chemicals that have been used as chemical intermediates. Catalytic epoxidation of olefins affords an interesting production technology. We found a widely usable green route to the production of epoxides: A silicotungstate compound, [gamma-SiW10O34(H2O)2]4-, is synthesized by protonation of a divacant, lacunary, Keggin-type polyoxometalate of [gamma-...
A novel method for constructing supramolecular hybrids composed of polyoxometalates and photofunctional metal complexes was developed. A Ru(II) complex with phosphonate groups (RuP) strongly interacted with Zn(II) to afford a 2 : 1 trinuclear metal complex ([(RuP)2Zn](3+)). In dimethylsulfoxide, [(RuP)2Zn](3+) strongly interacted with a Keggin-type heteropolyoxometalate (Si-WPOM) to form a 1 : ...
In the asymmetric unit of the title salt, (C(5)H(12)NO)(6)[PMo(12)O(40)](2)·5C(5)H(11)NO, there are two independent α-Keggin-type [PMo(12)O(40)](3-) polyoxidoanions, which show characteristic features with respect to bond lengths and angles. One of the [CH(3)CH(2)C(=OH)N(CH(3))(2)](+) cations is hydrogen bonded to the neighboring polyoxidoanion through a C=O-H⋯O(bridge) hydrogen bond. The organ...
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