نتایج جستجو برای: keggin

تعداد نتایج: 480  

Journal: :Molecules 2008
Karima Ighilahriz Baya Boutemeur Fariza Chami Cherifa Rabia Maâmar Hamdi Safouane M Hamdi

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...

Journal: :Matter 2022

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...

Journal: :Science 2002
Gerhard Furrer Brian L Phillips Kai-Uwe Ulrich Rosemarie Pöthig William H Casey

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...

2009
Akbar Raissi Shabari Mehrdad Pourayoubi Dena Ghamari

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...

Journal: :Science 2003
Keigo Kamata Koji Yonehara Yasutaka Sumida Kazuya Yamaguchi Shiro Hikichi Noritaka Mizuno

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-...

Journal: :Faraday discussions 2015
Kenji Ohashi Hiroyuki Takeda Kazuhide Koike Osamu Ishitani

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 : ...

2012
Akbar Raissi Shabari Mehrdad Pourayoubi Shadi Derakhshan Rad

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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