Mechanism of the oxidation of glyoxylic and pyruvic acids by periodate

Maros, L.; Molnár-Perl, I.; Kövér, L.

doi:10.1039/p29760001337

Cited by 7 publications

(6 citation statements)

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“…Furthermore, it was noted that glycolic acid (CH 2 (OH)CO 2 H) does not practically react with the Mn oxidant that lends support the gem-diol forms of the reducing αoxo acids could be the actual reactive species. Moreover, it is supposed that enolization of pyruvic acid is not apparent here, which becomes prominent when pyruvic acid is used at much higher concentration and at pH higher than 6 [55], conditions far from the present experimental conditions. The absence of oxalic acid in the product solution for pyruvate redox further confirmed the nonreactivity of enol pyruvate in this reaction [56].…”

Section: [Mn 3 (μ-O) 4 (Phen) 4 (H 2 O) 2 ] 4+ + 3rcocoohmentioning

confidence: 68%

“…Stepwise one-electron transfer and retention of nuclearity as proposed above are supported by the fact that different oxidation levels of the binuclear catalase enzyme models preserve nuclearity [51], the various oxidation levels (S states) of the manganese cluster in PSII also apparently retain bond connectivity [2] and high valent manganese has a propensity to form (μ-oxo) complexes in weakly acidic media [52]. The oxidation rates of glyoxylic and pyruvic acids by periodate were increased on increasing pH, and the authors suggested the reactions proceed through the nucleophilic attack of periodate to the carbonyl group of the α-oxo acids where the hydrated forms were nonreactive [55]. However, a reverse trend was found in this study-an increase in the rate with decreasing pH that might be due to weaker reactivity of the reducing anions in comparison to their parent acids.…”

Section: [Mn 3 (μ-O) 4 (Phen) 4 (H 2 O) 2 ] 4+ + 3rcocoohmentioning

confidence: 99%

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Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media

Mandal

Das

Mukhopadhyay

2010

Int J of Chemical Kinetics

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In aqueous media, the Mn IV trimer [Mn IV 3 (μ-O) 4 (phen) 4 (H 2 O) 2 ] 4+ (1, phen = 1,10phenanthroline) equilibrates with its deprotonated from [Mn 3 (μ-O) 4 (phen) 4 (H 2 O)(OH)] 3+ (2). Among the several synthetic multinuclear oxo-and/or carboxylato-bridged manganese complexes known to date containing metal-bound water, to the best of our knowledge, 1 is one of the rare examples that deprotonates (1 2 + H + ; pK a = 4.00 (±0.15) at 25.0 • C, I = 1.0 mol dm −3 , maintained with NaNO 3 ) at physiological pH. In aqueous media (pH 2-4), 1 oxidizes both glyoxylic and pyruvic acids to formic and acetic acid, respectively, along with the formation of CO 2 , the end manganese state being Mn II . Kinetic studies suggest that the species 1, its deprotonated form 2, the reducing acids (HA), and their conjugate bases (A − ) all take part in the reaction. The oxidant 1 is found to be more reactive than its conjugate base 2, and HA reacts faster than A − in reducing 1 or 2. The gem-diol form of the α-oxo acids (especially for glyoxylic acid) is the possible reducing species. The Mn IV 3 to Mn II transition in the present observation proceeds through the intermediate generation of the spectrally characterized mixed-valent Mn III Mn IV dimer that quickly collapses to Mn II . The observed rates of glyoxylic or pyruvic acid oxidation do not depend on the variation of 1,10-phenanthroline content of the solution, indicating the absence of any phen-releasing preequilibrium of the title complex in solution. The reactions rates were found to be lowered in media enriched with D 2 O in comparison to that in H 2 O and a rate-limiting one electron one proton (1e, 1H + ) electroprotic mechanism is proposed. C

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Section: [Mn 3 (μ-O) 4 (Phen) 4 (H 2 O) 2 ] 4+ + 3rcocoohmentioning

confidence: 68%

Section: [Mn 3 (μ-O) 4 (Phen) 4 (H 2 O) 2 ] 4+ + 3rcocoohmentioning

confidence: 99%

Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media

Mandal

Das

Mukhopadhyay

2010

Int J of Chemical Kinetics

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“…We, in this report, describe the kinetics * Author for correspondence and mechanism of pyruvate oxidation by the silver(III) complex under reference. We found kinetic evidence that the title complex oxidises glyoxylic acid by a two step one-electron transfer process [5], and thus we thought it worthwhile to oxidise pyruvic acid by the silver(III) complex to substantiate (or, compare) the mechanistic aspects of electron transfer as glyoxylic acid and pyruvic acid are in many ways kinetically comparable in their oxidations [15][16][17].…”

Section: Introductionmentioning

confidence: 95%

“…Mechanistic studies on pyruvate oxidation by highervalent metals are not very common [15][16][17][18][19]. Silver(III) in the title complex is much stabilised by the acyclic tetraaza ligand and is inert to substitution (d 8 ).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of oxidation of pyruvic acid by [ethylenebis(biguanide)]silver(III) in aqueous acidic media

Das

Mukhopadhyay

2004

Transition Metal Chemistry

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The oxidation of pyruvic acid by the title silver(III) complex in aqueous acidic (pH, 1.1-4.5) media is described. The reaction products are MeCO 2 H and CO 2 , together with a colourless solution of the Ag + ion. The free ligand, ethylenebis(biguanide) is released in near-quantitative yield upon completion of the reduction. The parent complex, [Ag(H 2 L)] 3+ and one of its conjugate bases, [Ag(HL)] 2+ , participate in the reaction with both pyruvic acid (HPy) and the pyruvate anion (Py ) ) as the reactive reducing species. Ag + was found to be catalytically inactive. At 25.0°C, I ¼ 1.0 mol dm )3 , rate constants for the reactions [Ag(H 2 L)] 3+ + HPy (k 1 ), [Ag(H 2 L)] 3+ + Py ) (k 2 ), [Ag(HL)] 2+ + HPy (k 3 ) and [Ag(HL)] 2+ + Py ) (k 4 ) are k 1 ¼ (94 ± 6) · 10 )5 dm 3 mol )1 s )1 , (k 2 K a + k 3 K a1 ) ¼ (1.3 ± 0.1) · 10 )5 s )1 and k 4 ¼ (58 ± 4) · 10 )5 dm 3 mol )1 s )1 , respectively, where K a1 is the first acid dissociation constant of the [Ag(H 2 L)] 3+ and K a is for pyruvic acid. A comparison between the k 1 and k 4 values is indicative of the judgement that k 2 ) k 3 . A one-electron inner-sphere redox mechanism seems more justified than an outersphere electron-transfer between the redox partners.

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“…P.; Bannister, C. E.; Margerum, D. W., to be submitted for publication. (12) Pagenkopf, G. K.; Margerum, D. W. J. Am.…”

mentioning

confidence: 99%

Oxidative decarboxylation of glyoxylate ion by a deprotonated-amine copper(III)-peptide complex

Kirksey¹,

Margerum²

1979

Inorg. Chem.

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Mechanism of the oxidation of glyoxylic and pyruvic acids by periodate

Cited by 7 publications

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Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media

Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media

Kinetics of oxidation of pyruvic acid by [ethylenebis(biguanide)]silver(III) in aqueous acidic media

Oxidative decarboxylation of glyoxylate ion by a deprotonated-amine copper(III)-peptide complex

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Mechanism of the oxidation of glyoxylic and pyruvic acids by periodate

Cited by 7 publications

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Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn3O4}4+ core in aqueous media

Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn3O4}4+ core in aqueous media

Kinetics of oxidation of pyruvic acid by [ethylenebis(biguanide)]silver(III) in aqueous acidic media

Oxidative decarboxylation of glyoxylate ion by a deprotonated-amine copper(III)-peptide complex

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Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media

Mechanistic studies on the oxidation of glyoxylic and pyruvic acids by a {Mn₃O₄}⁴⁺ core in aqueous media