نتایج جستجو برای: keggin

تعداد نتایج: 480  

Journal: :Inorganic chemistry frontiers 2021

H+ modulated charge-transfer in photoexcited covalently linked W and Mo Keggin-bodipy conjugates is demonstrated using transient absorption spectroscopy photoluminescence. Adding acid switches on (W) or accelerates (Mo) charge separation.

Journal: :Chemical communications 2015
Jung-Ho Son William H Casey

Caps in α-Keggin-type polyoxometalates [PM2Nb12O40](9-) (M: Nb[double bond, length as m-dash]O or V[double bond, length as m-dash]O) can be removed in basic condition to produce uncapped [PNb12O40](15-). Transmetalation or capping occurs from the reaction of [PNb14O42](9-) or [PNb12O40](15-) with either Sb2O3 or V2O5 to form [PSb2Nb12O40](9-) or [PV2Nb12O42](9-), respectively.

Journal: :Chemical communications 2012
Huanqiu Zhang Jun Peng Yan Shen Xia Yu Fang Zhang Jilan Mei Bin Li Liming Zhang

Fluorescent microtubes based on α-Keggin tungstosilicate and fluorescein (SiW(12)-F) have been obtained by using a simple method, which present tunable photoluminescence from sky blue to green to red by variation of excitation light. The SiW(12) component can inhibit photobleaching of fluorescein.

Journal: :Chemical communications 2012
Toshihiro Takashima Akira Yamaguchi Kazuhito Hashimoto Ryuhei Nakamura

Using carbon monoxide as a probe molecule for the oxidation state of Cu ions, we demonstrated that anchored polynuclear charge-transfer complexes consisting of Ce(III) ions and Cu(II)-substituted Keggin-type polyoxotungstates function as efficient visible-light-driven multielectron-transfer catalysts.

Journal: :Chemical communications 2010
Xiuli Wang Hailiang Hu Guocheng Liu Hongyan Lin Aixiang Tian

A novel (3,4)-connected 3D self-penetrating metal-organic framework with a nanometre-scale cavity constructed from metallacalix[4]arene building blocks and Keggin-type polyanions has been obtained by using a 1,3-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)propane ligand.

Journal: :Chemical communications 2012
Pingping Zhao Yan Leng Mingjue Zhang Jun Wang Yajing Wu Jun Huang

An ionic solid catalyst by pairing Keggin polyoxometalate-anions with Pd(II)-coordinated nitrile-tethered ionic liquid cations was synthesized, characterized, and tested for aerobic oxidation of benzene to biphenyl. A unique heterogeneous intramolecular electron transfer mechanism is proposed to understand its high activity.

2004
Haichao Liu Enrique Iglesia

H5PV2Mo10O40 polyoxometallate Keggin clusters supported on ZrO2, TiO2, SiO2, and Al2O3 are effective catalysts for CH3OH oxidation reactions to form HCHO, methyl formate (MF), and dimethoxymethane (DMM). Rates and selectivities and the structure of supported clusters depend on the surface properties of the oxide supports. Raman spectroscopy showed that Keggin structures remained essentially int...

2014
Gijo Raj Colas Swalus Eglantine Arendt Pierre Eloy Michel Devillers Eric M Gaigneaux

The hybridization of polyoxometalates (POMs) through an organic-inorganic association offers several processing advantages in the design of heterogeneous catalysts. A clear understanding of the organization of these hybrid materials on solid surfaces is necessary to optimise their properties. Herein, we report for the first time the organization of Keggin phosphotungstic [PW12O40](3-) and Wells...

Journal: :Proceedings of the National Academy of Sciences 2011

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