نتایج جستجو برای: α keggin

تعداد نتایج: 165395  

Journal: :Chemical communications 2010
Lik H Wee Sneha R Bajpe Nikki Janssens Ive Hermans Kristof Houthoofd Christine E A Kirschhock Johan A Martens

Nanomaterial of Cu(3)(BTC)(2) (BTC = benzene tricarboxylic acid) incorporating Keggin heteropolyacid conveniently prepared at room temperature and recovered by freeze drying outperforms ultrastable Y zeolite in acid catalysed esterification reaction.

Journal: :Chemical communications 2014
Kazuhisa Yajima Kazuya Yamaguchi Noritaka Mizuno

In the presence of Keggin-type phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, oxidative dimerization of various kinds of primary thioamides including aromatic, heterocyclic, and aliphatic ones efficiently proceeded to give the corresponding 3,5-disubstituted 1,2,4-thiadiazoles in excellent yields.

Journal: :Dalton transactions 2008
Bogdan Botar Paul Kögerler

The effect of acetate concentration on the formation of {SiW10Fe2}-based complexes is demonstrated by the synthesis of an open-shell diiron tungstosilicate derivative featuring two rotational Keggin isomer units.

Journal: :Chemical communications 2007
Xin-Long Wang Chao Qin En-Bo Wang Zhong-Min Su

Threading molecular square "beads" on a twofold interpenetrated diamondoid skeleton gives a new type of 3D metal-organic polyrotaxane framework with large channels, in which nanosized Keggin anions as guests are encapsulated for the first time.

2013
Haijun Pang Carlos J. Gómez-García Jun Peng Huiyuan Ma Chunjing Zhang Qingyin Wu

The rational self-assembly of mono-lacunary Keggin clusters with 4d and 4f metal salts via a conventional method has yielded two novel polyoxometalate-based 4d–4f heterometallic compounds containing lacunary Keggin anions connected to ten metal atoms: {[Ag{Ag2(H2O)4}{Ln(H2O)6}2H ⊂ {SiW11Ln(H2O)4O39}2]·nH2O (Ln = Ce and n = 7 for 1, Ln = Pr and n = 3 for 2). Their structures were determined by s...

Journal: :Dalton transactions 2017
A C Colusso M B Cortie A Dowd A M McDonagh

A hybrid surfactant/polyoxometalate compound was synthesized by combining isopolytungstate anions with the cationic surfactant cetyltrimethylammonium bromide (CTA-Br) to produce a hierarchical compound that we identify as (CTA)7[H2W12O40]Cl·2H2O. At room temperature the compound consisted of hexagonally ordered sheets of Keggin ions, with an intervening gallery containing alkyl-chains of the or...

Journal: :Chemical communications 2009
Scott G Mitchell Sumit Khanra Haralampos N Miras Thomas Boyd De-Liang Long Leroy Cronin

Two topologically equivalent triangular POM aggregates based upon the Keggin () and Dawson () cluster species, with distinctive double {W-O-M} intra-molecular linkages involving Mn(III) and Co(III) ions are presented; both these compounds demonstrate electrocatalytic activity.

2013
Zhiqi Wang Juan Navarrete

A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Brønsted acid sites and acidity strength in comparison with the bare support. At 100 ̊C, the 30 wt% H3PW12O40/Zr-MCM-48 contained 174 mol/g Brønsted acid sites which were 21.7 times greater tha...

Journal: :Dalton transactions 2010
Shiwei Lin Wenli Liu Yangguang Li Qiong Wu Enbo Wang Zhiming Zhang

Ionothermal synthesis was applied to the formation of polyoxometalates (POMs) and two new compounds [EMIM](8)Na(9)[WFe(9)(micro(3)-O)(3)(micro(2)-OH)(6)O(4)H(2)O(SiW(9)O(34))(3)].7H(2)O (, [EMIM](8)Na(9)[].7H(2)O, EMIM = 1-ethyl-3-methylimidazolium) and [EMIM](4)[SiMo(12)O(40)].12H(2)O (), have been successfully produced in the ionic liquid (IL) [EMIM](4)Br. They were characterized by single-cr...

Journal: :Chemical communications 2014
Jian-Qiang Shen Ying Zhang Zhi-Ming Zhang Yang-Guang Li Yan-Qing Gao En-Bo Wang

Two phosphoniobate-based 3D frameworks were firstly constructed using the hexa-capped Keggin polyoxoniobates [PNb12O40(VO)6](3-) and copper cations. Photocatalytic studies indicated that the hybrid materials exhibit photocatalytic hydrogen evolution activity.

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