ChemInform Abstract: Product and Kinetic Study of the Oxidation of Thioethers by Cerium(IV) Ammonium Nitrate in Acetic Acid

Baciocchi, Enrico; Intini, D.; Piermattei, Alessio; Rol, Cesare; Ruzziconi, Renzo

doi:10.1002/chin.199022072

Cited by 12 publications

(17 citation statements)

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“…Thioanisole (Aldrich) was distilled prior to use to a purity of 99.5%; benzyl phenyl sulfide, 4- methylthioanisole, and thiophenol (Aldrich) were used as supplied (purity >99%). The compounds 3 and 4 were obtained with purity >99% (HPLC) by the reaction of 4-mercaptobenzenesulfonic acid with benzyl or 4-methoxybenzyl chloride, respectively, in the presence of anhydrous potassium carbonate in refluxing acetone . 4-Mercaptobenzenesulfonic acid was prepared as follows: 4-nitrobenzyl chloride was sulfonated to sodium 4-nitrobenzenesulfonate, subsequently reduced to 4-aminobenzenesulfonic acid and converted into 4-mercaptobenzenesulfonic acid according to a literature procedure …”

Section: Methodsmentioning

confidence: 99%

Generation and Reactivity of Aromatic Thioether Radical Cations in Aqueous Solution As Studied by Pulse Radiolysis

1997

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The radical cations of thioanisole (1), p-methylthioanisole (2), and the benzyl phenyl sulfides 3-5 have been produced by pulse radiolysis in aqueous solutions, using SO 4 •-or Tl 2+ as oxidizing species. The radical cations 1 •+ -5 •+ exhibit very similar UV spectra, with strong absorptions between 300-350 and 500-600 nm. In contrast to aliphatic thioether radical cations, 1 •+ -5 •+ do not undergo dimerization (via formation of a three-electron bond with the parent thioethers). In the absence of bases, 1 •+ is a long-lived species with a lifetime >30 ms, whereas 3 •+ , 4 •+ , and 5 •+ decay rapidly by both C-S bond and C-H bond cleavage with k C-H ) 1.3 × 10 3 s -1 and k C-S ) 1.3 × 10 3 s -1 for 3 •+ and k C-H ) 0.95 × 10 3 s -1 and k C-S ) 2.65 × 10 3 s -1 for 4 •+ . In the presence of OH -or HPO 4 2-, also 1 •+ undergoes a deprotonation process, with a rate larger than those of the benzyl phenyl sulfide radical cations. For example, the rate constant for the OH --induced deprotonation is 3.4 × 10 7 M -1 s -1 for 1 •+ and 9.5 × 10 6 M -1 s -1 for 3 •+ . Thioanisole radical cation 1 •+ was also produced by reduction of thioanisole sulfoxide. Under these conditions, it was possible to study the reaction of 1 •+ with a number of nucleophiles or electron donors. It was found that 1 •+ reacts with I -, N 3 -, PhS -, PhSH, Br -, and SCN -by an electron transfer mechanism, producing the oxidized form of the nucleophile. This reaction is diffusion controlled with the first four nucleophiles, which are more easily oxidized than 1 (E°< 1.45 V); slower reactions were observed with SCN -(E°) 1.62 V) and with Br -(E°) 1.96 V). NO 3 -(E°) 2.3V) is unreactive (k < 10 6 M -1 s -1 ).

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Section: Methodsmentioning

confidence: 99%

Generation and Reactivity of Aromatic Thioether Radical Cations in Aqueous Solution As Studied by Pulse Radiolysis

1997

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“…A similar explanation has been offered in the Ce IV oxidation of organic sulfides. 22 Further, for the reactions where a larger reactivity of dialkyl sulfides compared to thioanisole has been observed, a direct oxygen transfer mechanism has been suggested. [23][24][25] of substituents in the oxidant and the substrate has the opposite effect on the rate of reaction i.e.…”

Section: ‡mentioning

confidence: 99%

Applicability and mathematical verification of the reactivity–selectivity principle in the oxidation of thioanisoles by oxo(salen)manganese(V) complexes

Chellamani¹,

Alhaji²,

Rajagopal³

1997

J. Chem. Soc., Perkin Trans. 2

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“…From these ρ values it is clear that the accelerating effect shown by the electron releasing groups (ERG) is significantly higher than that of the electron withdrawing groups. Such type of high ρ − value is already reported in electron transfer reaction between anilines and oxo(salen)‐chromium(V) ( ρ = −3.8), sulfoxidation of thioanisoles by Ce IV ( ρ = −3.3) and polypyridyl complexes ( ρ = −3.2) and the reactions of oxygen atom transfer from aryl sulfoxides to alkyl sulfides catalysed by rhenium(V) monoxo complex ( ρ = −4.6) . High ρ value is also observed in the oxidation reactions of organic sulfides by chloramine‐T ( ρ = −4.25), N‐chlorosaccharin ( ρ = −3.33), bromine ( ρ = −3.2), N‐bromobenzamide ( ρ = −3.18) and PTAAs by N‐chlorosaccharin ( ρ = −3.12) and ammonium meta vanadate ( ρ = −3.64) where electrophilic attack of the oxidizing species on the sulfur centre has been proposed as the rate‐determining step.…”

Section: Resultsmentioning

confidence: 57%

Section: Failure Of the Hammett Linear Free Energy Relationshipmentioning

confidence: 77%

A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

Subramaniam¹,

Rose

Rathinakumari

2016

J of Physical Organic Chem

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Mechanism of oxidative decarboxylation of phenylsulfinylacetic acids (PSAAs) by iron(III) polypyridyl complexes in aqueous acetonitrile medium has been investigated spectrophotometrically. 3+ is rationalized on the basis of coordination of a water molecule at the carbon atom adjacent to the ring nitrogen of the metal polypyridyl complexes by nucleophilic attack at higher concentrations. Electron-withdrawing and electron-releasing substituents in PSAA facilitate the reaction and Hammett correlation gives an upward 'V' shaped curve. The apparent upward curvature is rationalized based on the change in the rate determining step from electron transfer to nucleophilic attack, by changing the substituents from electron-releasing to electron-withdrawing groups. Electron-releasing substituents in PSAA accelerate the electron transfer from PSAA to the complex and also stabilize the intermediate through resonance interaction leading to negative reaction constants (ρ). Conversely, electron-withdrawing groups, while retarding the electron transfer exert an accelerating effect on the nucleophilic attack of H 2 O which leading to low magnitude of ρ + compared to high ρ À values of electron-releasing groups. Marcus theory is applied, and a fair agreement is seen with the experimental values.

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ChemInform Abstract: Product and Kinetic Study of the Oxidation of Thioethers by Cerium(IV) Ammonium Nitrate in Acetic Acid

Cited by 12 publications

References 0 publications

Generation and Reactivity of Aromatic Thioether Radical Cations in Aqueous Solution As Studied by Pulse Radiolysis

Generation and Reactivity of Aromatic Thioether Radical Cations in Aqueous Solution As Studied by Pulse Radiolysis

Applicability and mathematical verification of the reactivity–selectivity principle in the oxidation of thioanisoles by oxo(salen)manganese(V) complexes

A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

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