نتایج جستجو برای: keggin
تعداد نتایج: 480 فیلتر نتایج به سال:
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.
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.
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.
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.
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.
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.
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...
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...
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