A voltammetric study of Keggin-type heteropolymolybdate anions

Maeda, Kohji; Himeno, Sadayuki; Osakai, Toshiyuki; Saito, Atsuyoshi; Hori, Toshitaka

doi:10.1016/0022-0728(93)02936-c

Cited by 88 publications

(54 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…31 P NMR data are gathered in Table 1. The electrochemical behaviour of HII and H 2 II in MeCN had been previously studied by Himeno et al [22] As electrochemical data will be at the centre of the discussion, they were examined further. The results reported in Table 2 are in agreement with those reported by Himeno et al Solution data for HII and H 2 II were measured both for these species formed in situ by acidification of LiII and after isolation of (nBu 4 N) 4 [HPMo 12 O 40 ] and (nBu 4 N) 3 [H 2 PMo 12 O 40 ], respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Artero

Proust

2000

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

The reaction of phosphonium ylides with [PMo12O40]3− consists of successive single electron transfers leading to the formation of the 1e‐ and 2e‐reduced polyoxomolybdates [PMo12O40]4− and [PMo12O40]5−. The ylide is converted into the corresponding phosphonium cation via a radical‐cation intermediate. The reaction of phosphanes follows the same pathway but subsequent reactions with residual water produce protons which induce the disproportionation of [PMo12O40]4−. Authentic samples of heteropoly blues in different protonation states have been obtained from the reaction of phenyllithium with [PMo12O40]3− and subsequent protonation with triflic acid. On the basis of electrochemical and spectroscopic data, the reaction product of [PMo12O40]3− with triphenylphosphane, which has been previously described as the oxygen‐deficient species [PMo12O39]3−, is reformulated as [H2PMo12O40]3−.

show abstract

Section: Introductionmentioning

confidence: 99%

“…2 (2) It follows therefore that [HPMo 12 O 40 ] 3Ϫ cannot be isolated. Whether the more positive oxidation wave of [HPMo 12 O 40 ] 4Ϫ at 0.56 V/SCE is due to the 1e-oxidation of HI, as assumed by Himeno et al, [22] or to the 2e-oxidation of H 2 II resulting from the disproportionation of HI, remains to be established. Indeed, the R.D.E.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Artero

Proust

2000

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…Maeda et al examined the electrochemistry of 12-molybdophosphate in aqueous-organic solution. 29 The reduced form of 12-molybdophosphate was found to be more stable in aqueousorganic solution than in aqueous solution. Based on these results, optimizing the formation conditions of the reduced 12-molybdophosphate complex in aqueous-organic solution seems to enable one to determine a wider range of concentrations of P-PO4 3-than the phosphoantimonylmolybdenum blue method as a manual batch procedure.…”

mentioning

confidence: 99%

Determination of Phosphorus Based on the Formation of a Reduced Keggin-Type 12-Molybdophosphate Complex in an Aqueous-Organic Solution

2001

View full text Add to dashboard Cite

Extensive studies have been devoted to the determination of phosphorus as phosphate ion by the molybdenum blue method. There have been many reports on various modifications of this method in order to make the sensitivity and stability high. Various reductants, such as 1-amino-2-naphthol-4-sulfonic acid, stannous chloride(II), and ascorbic acid have been used to reduce the molybdophosphate complex. 1-11 However, it is known to be difficult for methods using 1-amino-2-naphthol-4-sulfonic acid and stannous chloride(II) to control both the pH and the temperature. 12 It is also well known that solvent extraction with ethyl acetate, 1-butylalcohol, 2-methyl-1-propylalcohol, and so on, makes the sensitivity high. 5,[13][14][15][16][17][18][19][20][21] Motomizu et al. reported that the formation of colored ionassociate between molybdophosphate and Malachite Green could be utilized to determine phosphorus in the ultra-trace range from 0.018 to 1.0 ng cm -3 . 22These highly sensitive methods contain a few careful procedures and require skill to determine P-PO4 3-with both high accuracy and precision. Molybdenum blue methods containing other metal ions, such as Sb(III), so-called phosphoantimonylmolybdenum blue method, has also usually been used as manual batch procedures. 2,3,23 Blomqvist and Westin reported in detail the effect of Cr(VI), Ge(VI), W(VI), and V(V) ions that have easily reacted with heteropolyoxometalate on the absorbance measurement in the phosphoantimonylmolybdenum blue method. 24 Various flowinjection analysis methods, that analyze phosphorus automatically, have also been developed. 2,3,25 It was also reported that organic phophorus and hydrolyzable phosphorus were converted into the orthophosphate ion for determining P-PO4 3-. 3,4,[25][26][27] In a previous report, the formation conditions of molybdophosphate and -arsenate complexes in aqueous solution were confirmed. 28 A few kinds of molybdophosphate complexes have been formed under high acidic conditions. The addition of water-miscible organic solvents, such as acetonitrile and acetone, made only 12-molybdophosphate stable. Maeda et al. examined the electrochemistry of 12-molybdophosphate in aqueous-organic solution. 29 The reduced form of 12-molybdophosphate was found to be more stable in aqueousorganic solution than in aqueous solution. Based on these results, optimizing the formation conditions of the reduced 12-molybdophosphate complex in aqueous-organic solution seems to enable one to determine a wider range of concentrations of P-PO4 3-than the phosphoantimonylmolybdenum blue method as a manual batch procedure. ExperimentalThe absorption spectra were recorded on a Hitachi Model U-2000 spectrophotometer using silica cells with path lengths of 0.1 and 1 cm. Spectroscopic measurements under various conditions were made at 25 ± 0.1˚C without any baseline correction; those under the optimum determining conditions were made at room temperature. All of the reagents were of analytical grade, and were used as received. Results and Discussion Optimizatio...

show abstract

“…a-(n-Bu 4 N) 3 [PMo 12 O 40 ] was prepared and purified according to the literature method [14]. 5À (II) can play a decisive role in the conversion process [8].…”

mentioning

confidence: 99%

Solvation Effect of Li⁺ on the Voltammetric Properties of [PMo₁₂O₄₀]³⁻. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures

Himeno¹,

Takamoto²,

Ueda³

et al. 2004

Electroanalysis

Self Cite

View full text Add to dashboard Cite

, the presence of Li produced a two-electron wave at nearly the same potential as the first oneelectron wave in acetonitrile or acetone. The voltammetric behavior of [PMo 12 O 40 ] 3À in a binary mixture of acetonitrile and solvent S was compared with those in a mixture of acetone and S. When the donor number (DN) of S > 20, the first two-electron wave was converted into one-electron waves in such binary mixtures. The conversion occurred at lower mole fractions of S in an acetonitrile S mixture than in an acetone S mixture. The 7 Li NMR results showed that the preferential solvating ability of Li with S was greater in the former mixture. A linear relationship was found between the iso-solvation point x iso (S) and the reciprocal of the difference between the DNs of S and acetonitrile, which gave the basis to explain the anomalies observed for a mixture of acetonitrile and H 2 O.

show abstract

A voltammetric study of Keggin-type heteropolymolybdate anions

Cited by 88 publications

References 17 publications

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Determination of Phosphorus Based on the Formation of a Reduced Keggin-Type 12-Molybdophosphate Complex in an Aqueous-Organic Solution

Solvation Effect of Li⁺ on the Voltammetric Properties of [PMo₁₂O₄₀]³⁻. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures

Contact Info

Product

Resources

About

A voltammetric study of Keggin-type heteropolymolybdate anions

Cited by 88 publications

References 17 publications

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Reduction of the Phosphododecamolybdate Ion by Phosphonium Ylides and Phosphanes

Determination of Phosphorus Based on the Formation of a Reduced Keggin-Type 12-Molybdophosphate Complex in an Aqueous-Organic Solution

Solvation Effect of Li+ on the Voltammetric Properties of [PMo12O40]3−. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures

Contact Info

Product

Resources

About

Solvation Effect of Li⁺ on the Voltammetric Properties of [PMo₁₂O₄₀]³⁻. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures