The “Fenton like” reaction of MoO43− involves two H2O2 molecules

Popivker, Inna; Zilbermann, Israel; Maimon, Eric; Cohen, Haim; Meyerstein, Dan

doi:10.1039/c3dt52333k

Cited by 18 publications

(4 citation statements)

References 12 publications

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“…It should be noted that in all the suggested mechanisms of reaction of a low-valent transition-metal complex with H 2 O 2 only one H 2 O 2 molecule is involved, [3][4][5][6][7][8][9][10][11][12][13][14][15] the results presented herein and in a new report on the reaction of H 2 O 2 with Mo V O 4 16 differ from this paradigm.…”

Section: Introductionmentioning

confidence: 65%

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Three H2O2 molecules are involved in the “Fenton-like” reaction between Co(H2O)62+ and H2O2

et al. 2014

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Co(II) complexes and Co(H2O)6(2+) are used as catalysts in advanced oxidation processes. Therefore it was decided to study the kinetics of reaction of Co(H2O)6(2+) with H2O2. Surprisingly, the kinetic results point out that the process involves three consecutive reactions, each of them requiring an H2O2 molecule, i.e. three H2O2 molecules ligate to the central cobalt cation prior to the formation of radicals. DFT analysis suggests that the transient (H2O)3Co(II)(OOH)2(H2O2) decomposes via: (H2O)3Co(II)(OOH)2(H2O2) → (H2O)3Co(II)(OOH)(˙OOH)(OH) + ˙OH ΔG(0) = -5.975 kcal mol(-1), with no evidence for the formation of a Co(III) transient. It is proposed that analogous mechanisms are involved whenever the redox potential of the central cation is too high to enable the reaction: M(H2O)6(n+) + H2O2 → M((n+1)+)aq + ˙OH + OH(-).

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Section: Introductionmentioning

confidence: 65%

“…An analogous mechanism was recently proposed for the reaction of H 2 O 2 with MoO 4 3− . 16 It was decided therefore to check whether an analogous mechanism is plausible in the presence of Co-(H 2 O) 6 2+ ions. For this purpose the free energy gain in the following reactions was calculated by DFT.…”

Section: Resultsmentioning

confidence: 99%

Three H2O2 molecules are involved in the “Fenton-like” reaction between Co(H2O)62+ and H2O2

et al. 2014

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“…However, reactive oxygen species such as hydrogen peroxide (H 2 O 2 ) and O2- are not only essential for lignification processes, they can also be transformed into highly reactive hydroxyl radicals in so called Fenton or Fenton-like reactions although in presence of redox active transition metals such as Cu(I), Fe(II) (Mithöfer et al, 2004), but also Cr III and VI (Sharmin et al, 2012) and, in vitro , also MoO42- (Aubry and Cazin, 1988; Aubry et al, 1989; Boehme and Brauer, 1992; Popivker et al, 2013). The observed increase in abundance of a variety of peroxidases but also other enzymes involved in antioxidative defense (glutathione S-transferases (GST) in both N regimes; monodehydroascorbate reductase (MDHAR) in N fed plants) as well as an altered regulation of the glyoxalase system (lactoglutathione lyase in nodules of N fix only), (Tables S4, S5) indeed indicate that tungsten interferes with oxidative homeostasis by inducing accumulation of ROS.…”

Section: Discussionmentioning

confidence: 99%

Molecular Mechanisms of Tungsten Toxicity Differ for Glycine max Depending on Nitrogen Regime

et al. 2019

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Tungsten (W) finds increasing application in military, aviation and household appliance industry, opening new paths into the environment. Since W shares certain chemical properties with the essential plant micronutrient molybdenum (Mo), it is proposed to inhibit enzymatic activity of molybdoenzymes [e.g., nitrate reductase (NR)] by replacing the Mo-ion bound to the co-factor. Recent studies suggest that W, much like other heavy metals, also exerts toxicity on its own. To create a comprehensive picture of tungsten stress, this study investigated the effects of W on growth and metabolism of soybean ( Glycine max ), depending on plant nitrogen regime [nitrate fed (N fed) vs. symbiotic N 2 fixation (N fix)] by combining plant physiological data (biomass production, starch and nutrient content, N 2 fixation, nitrate reductase activity) with root and nodule proteome data. Irrespective of N regime, NR activity and total N decreased with increasing W concentrations. Nodulation and therefore also N 2 fixation strongly declined at high W concentrations, particularly in N fix plants. However, N 2 fixation rate (g N fixed g −1 nodule dwt) remained unaffected by increasing W concentrations. Proteomic analysis revealed a strong decline in leghemoglobin and nitrogenase precursor levels (NifD), as well as an increase in abundance of proteins involved in secondary metabolism in N fix nodules. Taken together this indicates that, in contrast to the reported direct inhibition of NR, N 2 fixation appears to be indirectly inhibited by a decrease in nitrogenase synthesis due to W induced changes in nodule oxygen levels of N fix plants. Besides N metabolism, plants exhibited a strong reduction of shoot (both N regimes) and root (N fed only) biomass, an imbalance in nutrient levels and a failure of carbon metabolic pathways accompanied by an accumulation of starch at high tungsten concentrations, independent of N-regime. Proteomic data (available via ProteomeXchange with identifier PXD010877) demonstrated that the response to high W concentrations was independent of nodule functionality and dominated by several peroxidases and other general stress related proteins. Based on an evaluation of several W responsive proteotypic peptides, we identified a set of protein markers of W stress and possible targets for improved stress tolerance.

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“…The use of a molybdenum polyoxometalated compound depended on the evidences that molybdenum can act as catalyst in Fenton-like reactions [ 31 , 32 ]. However, molybdenum polyoxometalated compounds have not been used to this purpose until now [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

The Use of a Molybdenum Polyoxometalated Compound to Increase the Amount of Extractives from Wood Wastes

2018

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The treatment of wood wastes of Castanea sativa L., Quercus frainetto, Larix decidua, and Paulownia tomentosa S. in autoclave in the presence of micrometric crystals of H3PMo12O40 showed an impressive increase of the amount of extractives. The extractives were mainly constituted of insoluble compounds that were analyzed by using gas chromatography-mass spectrometry (GC-MS) after acetylation. The GC-MS analysis of the chloroform soluble fraction of the extractives obtained from sativa showed the presence of methyl hexadecanoate and octadecanoic acid, that of the extractives of frainetto showed the presence of octadecanal and some long chain hydrocarbons. decidua extracts showed the presence of large amounts of sesamin, while the extractives of P tomentosa revealed the presence of 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxycimmanaldehyde, and relevant amounts of long chain hydrocarbons. The insoluble fraction showed the presence of relevant amounts of several carbohydrates and, in the case of C. sativa, of inositol.

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The “Fenton like” reaction of MoO43− involves two H2O2 molecules

Abstract: Surprisingly the oxidation of MoO4(3-) by H2O2 involves two H2O2 molecules. It is proposed that generally when the reaction of a reducing agent with H2O2, to form a single electron oxidized product and a hydroxyl radical, is endothermic the reaction involves more than one H2O2 molecule.

Cited by 18 publications

References 12 publications

Three H2O2 molecules are involved in the “Fenton-like” reaction between Co(H2O)62+ and H2O2

Three H2O2 molecules are involved in the “Fenton-like” reaction between Co(H2O)62+ and H2O2

Molecular Mechanisms of Tungsten Toxicity Differ for Glycine max Depending on Nitrogen Regime

The Use of a Molybdenum Polyoxometalated Compound to Increase the Amount of Extractives from Wood Wastes

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