Stepwise base decomposition of 12-tungstosilicate(4–)

Kepert, David L.; Kyle, J.

doi:10.1039/dt9780000137

Cited by 33 publications

(38 citation statements)

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“…A general scheme for the decomposition of WSiA in aqueous solution with increasing pH was proposed in the literature. 16 WO . A quantitative determination of speciation of WSiA over the pH range 3-13.5, performed by Smith and Patrick by NMR spectroscopy, 22 showed that the Keggin [SiW 12 O 40 ] 4− anion is stable up to pH 3.7; the main component in the pH range from 3.8-9.2 is the lacunary [SiW 11 O 39 ] 8− monovacant anion, which is decomposed with further increase in the pH value.…”

Section: Uv Spectramentioning

confidence: 99%

“…1,3,9−15 It was shown that many POMs degrade into a mixture of inorganic products in aqueous solution. 1 Kepert and Kyle 16,17 studied the decomposition of Keggin anions containing silicon, phosphorus or boron as the central, heteroatom and tungsten as the addenda metal atom. These authors found that the equilibrium reaction in solution proceeds in three distinct stages, with [SiW 11 O 39 ] 8− and [SiW 9 O 34 ] 10− as intermediates.…”

Section: Introductionmentioning

confidence: 99%

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A study of 12-tungstosilicic and 12-molybdophosphoric acids in solution

Bajuk‐Bogdanović

Holclajtner-Antunović

Todorović³

et al. 2008

J Serb Chem Soc

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The behaviour of two heteropolyacids (HPAs) with quite different stability in aqueous solutions was systematically investigated by UV, IR and NMR spectroscopy and potentiometric titration. It was shown that the Keggin structure of 12-tungstosilicic acid (H 4 SiW 12 O 40 , WSiA) anion was sustained over a wide range of pH from 1.0 to 7.0, while the same anion type of 12-molybdophosphoric acid (H 3 PMo 12 O 40 , MoPA) was present only at pH 1.0. This means that under physiological conditions WSiA is dominantly present in the form of a Keggin-anion, whereas the structure of MoPA is completely decomposed to molybdate and phosphate. The obtained results are of special importance for bio-medical and catalytic applications of these compounds and for a better understanding of the mechanism of their action.

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Section: Uv Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A study of 12-tungstosilicic and 12-molybdophosphoric acids in solution

Bajuk‐Bogdanović

Holclajtner-Antunović

Todorović³

et al. 2008

J Serb Chem Soc

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“…22) In our study, all solid-state Zscheme composites were prepared from PW 12 and TiO 2 using a layer-by-layer (LBL) deposition method and were applied to a gaseous phase reaction.…”

Section: Introductionmentioning

confidence: 99%

“…PW 12 exists as a trivalent anion in water and is stable at low pH (<2), 22) whereas TiO 2 nanoparticles (d = 6 nm) have a positive charge in such an acidic condition because the isoelectric point of nanosized TiO 2 is 3.8 to 6.…”

Section: Introductionmentioning

confidence: 99%

Nano/microsized TiO<sub>2</sub> composite photocatalysts for environmental purification

Yanagida

2018

J. Ceram. Soc. Japan

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TiO 2 photocatalyst is one of the most important photocatalysts for practical use owing to its low toxicity, high chemical stability, natural abundance, and strong oxidation power. However, its low quantum efficiency which is derived from fast electron-charge recombination and its low decomposition rate against organic compounds in low concentration and/or low affinity for TiO 2 surface is problematic for environmental purification. To overcome these problems, functionalized photocatalysts that have a nano/microsized structure were prepared by combining TiO 2 and other materials in our study. A Z-scheme photocatalyst thin film, a TiO 2 -coated porous glass composite with high adsorption capacity, and a TiO 2 -coated stainless mesh for electric field-assisted photocatalysis were prepared using liquid and colloidal processes. This study reports the photocatalytic properties of these composites in air and water environments and their decomposition mechanisms.

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“…However, mono-(terpyridine) complexes (ratio 1:1), especially with the Cu n ion, can give rise to mononuclear (Rojo, Vlasse & Beltran, 1983;Allmann, Kremer & Kucharzcyk, 1984) and polynuclear species (Anderson, Packard & Wicholas, 1976;Rojo, Arriortua, Ruiz, Darriet, Villeneuve & Beltran-Porter, 1987). The coordination chemistry of the cyanato anion (NCO)-has already been considered extensively (Norbury, 1975;Kohout, Hvastijova & Gazo, 1978;Kepert, Kucharski & White, 1980). However, less attention has been paid to the study of (cyanato)nickel(II) complexes.…”

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confidence: 99%