Charge dependence of one-electron redox potentials of Keggin-type heteropolyoxometalate anions

Maeda, Kohji; Katano, Hajime; Osakai, Toshiyuki; Himeno, Sadayuki; Saito, Atsuyoshi

doi:10.1016/0022-0728(95)03872-e

Cited by 68 publications

(50 citation statements)

References 20 publications

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“…The direct dependence of the relationship of E 1=2 with the one-electron redox processes is consistent with the original interpretations of Pope and Varga [42], who suggested an electrostatic effect of ionic charge for [XM 12 O 40 ] nÀ (n ¼ 3-7) upon E 1=2 in aqueous media. Maeda et al [23,24] have since confirmed the same dependence and general linear relationship in nonaqueous media. Our results of Fig.…”

Section: Resultsmentioning

confidence: 52%

“…Specifically, we have exploited 1,3-dialkylimidazolium salts that are liquid at room temperature as dual purpose media-solvent and electrolyte -in which to study the electrochemical response of the Keggin polyoxoanion. Although this response is thoroughly understood [7,[22][23][24][25][26][27][28][29] in conventional solvents, both aqueous and organic, which require the use of added supporting electrolytes, no reports of POM electrochemistry in ILs have appeared to date.…”

Section: Introductionmentioning

confidence: 97%

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Redox chemistry of the Keggin heteropolyoxotungstate anion in ionic liquids

Chiang

Dzielawa

Dietz

et al. 2004

Journal of Electroanalytical Chemistry

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Section: Resultsmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 97%

Redox chemistry of the Keggin heteropolyoxotungstate anion in ionic liquids

Chiang

Dzielawa

Dietz

et al. 2004

Journal of Electroanalytical Chemistry

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“…The interest in these compounds comes from their catalytic and photocatalytic properties. 2 -6 Osakai et al 7,8 have demonstrated that phosphotungstic acid has a solvatochromic electrochemical behaviour as a combined function of the dielectric constant (Born solvation model) and electron acceptor ability (Guttman acceptor number) of the solvent. Therefore, it seems possible to finely tune the redox behaviour of these oxoclusters by controlling intermolecular interactions with different polymer matrices.…”

Section: Introductionmentioning

confidence: 98%

Micro‐ and nanocomposites of Keggin heteropolymetalates in cellulose esters

Oliveira

Schneider

Siervo

et al. 2002

Surface & Interface Analysis

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Composites of Keggin heteropolymetalates have been prepared and characterized by SEM, XPS, 31 P-magic angle spinning/nuclear magnetic resonance and differential scanning calorimetry. The phosphotungstic acid and phosphomolybdic acid form nanocomposites where the oxocluster structure is preserved and is highly dispersed over the material, probably inserted between the polymeric chains. Phosphovanadotungstic clusters suffer partial decomposition during composite formation, resulting in a biphasic microcomposite. The decomposition product, phosphotungstic acid presents surface segregation as shown by comparison of XPS and nuclear magnetic resonance results.

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“…Hence, the LUMOs of molybdate HPAs more readily accept electrons than those of tungstates HPAs; this means that the molybdate HPAs are more powerful oxidizing reagents than the corresponding tungstates. The experimental results showed that the reduction potentials of [SiMo 12 [6,37] . This is why molybdate HPAs are usually selected as oxidative catalysts instead of tungstate HPAs.…”

Section: α-Keggin Type Hpasmentioning

confidence: 98%

Effects of vanadium(V)-substitution on the oxidative properties of α-Keggin-type heteropolyanion clusters—progress in DFT theoretical studies

Wang

et al. 2009

Sci. China Ser. B-Chem.

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The redox properties of α-Keggin-type heteropolyanion clusters [XM 12 O 40 ] n− (X = Si, P; M = Mo, W) mainly depend on their constituent outer metal-oxygen cages {M 12 O 36 }. They act as "reservoirs", through which the transfer and transition of electrons and protons may occur. At the atomic and molecular level, the redox properties of these clusters can be controlled and also tuned by modifying the metal M in the cages and the central heteroatom X of the clusters. Combined with relevant experimental results, this review summarizes our recent theoretical investigations of the effect of vanadium substitution on the redox properties of Keggin anion clusters. Theoretical modeling and calculation results showed that the oxidative ability of the modified species was increased by partial substitution of the cage M atoms of the Keggin clusters by vanadium atoms which have lower electronegativity. A linear correlation between the catalytic efficiency per vanadium atom and the microstructures of the vanadium(V)-substituted heteropolyanions [PV n Mo 12−n O 40 ] (3+n)− (n = 1-3) was established for the first time. This relationship may be suitable to interpret the catalytic behavior of the title compounds in the hydroxylation of benzene to phenol, and may also be used in understanding other reactions such as the oxidative dehydrogenation of isobutyric acid and the nitration of adamantine. The establishment of this nearly linear structure-property relationship may lay the foundations of understanding the behavior of the title compounds in homogeneous catalytic oxidation reactions, and may direct the design of future catalysts and the choice of other catalytic reactions.polyoxometalates, α-Keggin-type, heteropolyanions, vanadium substitution, oxidative property, density functional theory (DFT)

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Charge dependence of one-electron redox potentials of Keggin-type heteropolyoxometalate anions

Cited by 68 publications

References 20 publications

Redox chemistry of the Keggin heteropolyoxotungstate anion in ionic liquids

Redox chemistry of the Keggin heteropolyoxotungstate anion in ionic liquids

Micro‐ and nanocomposites of Keggin heteropolymetalates in cellulose esters

Effects of vanadium(V)-substitution on the oxidative properties of α-Keggin-type heteropolyanion clusters—progress in DFT theoretical studies

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