Electron transfer reactions of iron (III) - polypyridyl complexes with organic sulphides

Balakumar, S.; Thanasekaran, Pounraj; Rajagopal, Seenivasan; Ramaraj, Ramasamy

doi:10.1016/0040-4020(95)00160-a

Cited by 25 publications

(20 citation statements)

References 43 publications

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“…1,2,6 -10 To get an idea of the reactivity of these biologically important substrates, organic sulfides and sulfoxides, we have initiated a systematic study on the kinetics and mechanism of oxidation of these substrates with several electrophilic oxo(salen)metal complexes 11 -15 and iron(III) -polypyridyl complexes. 16,17 Both organic sulfides and sulfoxides behave as nucleophiles towards oxo(salen)manganese(V) 11, 12 and oxo(salen)iron 14,15 complexes. With oxo(salen)iron complexes the reactivity and reaction constant values are smaller for sulfoxides compared to sulfides.…”

Section: Introductionmentioning

confidence: 99%

Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl complexes

et al. 2004

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Section: Introductionmentioning

confidence: 99%

Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl complexes

et al. 2004

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“…According to this concept, the rate constant (k 12 ) for an ET reaction (Eqn 9) depends on intrinsic reactivity of the redox couples involved, i.e. self-exchange rate constants at zero driving force, k 11 and k 22 and the thermodynamics of the couples.…”

Section: Application Of Marcus Theory Of Electron Transfermentioning

confidence: 99%

“…As the iron(II) polypyridyl complexes have high molar extinction coefficients of the order 1 × 10 4 M À1 cm À1 and the corresponding iron(III) complexes are transparent in the above absorption regions, [6,22] the reactions of PSAAs with [Fe(NN) 3 ] 3+ complexes were monitored by measuring the increase in absorbance with time as shown in Fig. 2.…”

Section: Kinetic Measurementsmentioning

confidence: 99%

“…The value of k 22 for iSO •+ /iSO couple can be determined from an iterative procedure, i.e. a value of k 22 is guessed and plugged into Eqn 12 to calculate f. A plot of log k 12 -0.5 (log k 11 -log f 12 ) versus log K 12 is made, and from mean least-square calculations, the intercept and slope of such plots are determined.…”

Section: Application Of Marcus Theory Of Electron Transfermentioning

confidence: 99%

“…a value of k 22 is guessed and plugged into Eqn 12 to calculate f. A plot of log k 12 -0.5 (log k 11 -log f 12 ) versus log K 12 is made, and from mean least-square calculations, the intercept and slope of such plots are determined. From the intercept a new estimated value of k 22 is obtained, and this is then used to calculate a new log f. The entire iterative process was repeated until successive estimates of k 22 …”

Section: Application Of Marcus Theory Of Electron Transfermentioning

confidence: 99%

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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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Mechanism of (Salen)manganese(III)‐Catalyzed Oxidation of Aryl Phenyl Sulfides with Sodium Hypochlorite

Chellamani

Harikengaram

2011

Helvetica Chimica Acta

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The oxidation of 4-substituted phenyl phenyl sulfides was carried out with several oxo(salen)manganese(V) complexes in MeCN/H 2 O 9 : 1. The kinetic data show that the reaction is first-order each in the oxidant and sulfide. Electron-attracting substituents in the sulfides and electron-releasing substituents in salen of the oxo(salen)manganese(V) complexes reduce the rate of oxidation. A Hammett analysis of the rate constants for the oxidation of 4-substituted phenyl phenyl sulfides gives a negative 1 value (1 ¼ À 2.16) indicating an electron-deficient transition state. The log k 2 values observed in the oxidation of each 4-substituted phenyl phenyl sulfide by substituted oxo(salen)manganese(V) complexes also correlate with Hammett s constants, giving a positive 1 value. The substituent-, acid-, and solvent-effect studies indicate direct O-atom transfer from the oxidant to the substrate in the rate-determining step.Introduction. -To mimic active intermediates in enzyme-catalyzed oxidation reactions, porphyrinato-and (salen)manganese, -chromium, -ruthenium, and -iron complexes (salen ¼ N,N'-bis (salicylidene) [27], and oxo(salen)iron [28] follow an S N 2 mechanism. However, a dual mechanism has been proposed in some oxidation reactions [29].With the aim of establishing the optimum conditions for the synthesis of sulfoxides and sulfones and the mechanism of oxometal ion oxidation of organic sufides, we have studied extensively the kinetics and mechanism of oxo(salen)metal ion oxidation of organic sulfur compounds [20]

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Electron transfer reactions of iron (III) - polypyridyl complexes with organic sulphides

Cited by 25 publications

References 43 publications

Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl complexes

Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl 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

Mechanism of (Salen)manganese(III)‐Catalyzed Oxidation of Aryl Phenyl Sulfides with Sodium Hypochlorite

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