Kinetics and Mechanism of Oxidation of <i>L</i>‐Cystine by Hexacyanoferrate(III) in Alkaline Medium

Nowduri, Annapurna; Adari, Kalyan Kumar; Gollapalli, Nageswara Rao; Vani, P.

doi:10.1155/2009/615750

Cited by 19 publications

(9 citation statements)

References 15 publications

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“…Only ascorbic acid and l-cysteine interfered to a significant extent. This is due to the fact that the hexacyanoferrate (III) produced in the turnip peroxidase reaction can be reduced by ascorbic acid and is able to oxidize lcysteine [33]. From this it can be noted that the proposed turnip …”

Section: Selectivity Against Interferencesmentioning

confidence: 95%

A mediated turnip tissue paper-based amperometric hydrogen peroxide biosensor

Sekar

Shaegh

et al. 2015

Sensors and Actuators B: Chemical

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Section: Selectivity Against Interferencesmentioning

confidence: 95%

A mediated turnip tissue paper-based amperometric hydrogen peroxide biosensor

Sekar

Shaegh

et al. 2015

Sensors and Actuators B: Chemical

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“…Its thiol group (–SH), thiolate ion (CS − ), and thiyl radical species (CS * ) are capable of initiating reduction reaction in acidic, aqueous, or buffer media [ 11 – 13 ]. The electron transfer reactions of l-cysteine have been investigated in a good number of researches such as reduction of trinuclear Mn(IV) species in which the rate was found to increase in aqua media [ 14 ], [Mn 4 O 6 ] 4+ core resulted in a significant decrease in the observed second-order rate constants in aqua media enriched with deuterium water and a proton-mixed single electron transfer reaction was proposed [ 15 ], 11-tungstophosphovanate(V) resulted in a first order with respect to [redox species] [ 16 ], Hexacyanoferrate(III) showed an increased reaction rate with increase in hydroxide ion concentration and the product was found to be sulfenic acid [ 17 ], and [CoSalophen] + complex established the importance of deprotonated and protonated form of l-cysteine in the electron transfer process [ 18 ]; in the view to gain more understanding of the character of enzymes containing thiol group in bio-systems.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and Kinetic Investigation of Reaction of Acriflavine with L-cysteine in Aqueous Medium

Nkole

Idris

2021

Chemistry Africa

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Graphic abstract The kinetic investigation of reaction of 3,6-diamino-10-methylacridin-10-ium chloride (acriflavine) with l-cysteine in aqueous acidic medium at maximum absorption = 460 nm, ionic strength (I) = 0.1 mol dm −3 and temperature (T) = 307 K has been carried out spectrophotometrically. Using a pseudo first order approach, the rate of the redox reaction resulted to first order with respect to the [acriflavine, (AF)] and [l-cysteine, (CSH)] and second order total. Stoichiometric determination confirms that a mole of the acriflavine is consumed by a mole of l-cysteine at a time for the attainment of product formation. The reaction followed a one-way acid independence path. The adjustment in ionic strength (NaCl) and solvent polarity (water/acetone mixture) of the reaction system showed no reasonable effect and there was a fairly decrease in the reaction rate, respectively. The reaction rate is also characterised by neither catalysis nor inhibition of added ions. The negative magnitude of entropy of activation, S ‡ , (− 151.39 ± 031 J mol −1 K −1 ) and positive value of enthalpy of activation, H ‡ , (+ 31.378 ± 030 kJ mol −1 ) suggest that the reaction proceeds via an associative pathway and reasonable energy are needed to lower the activation energy for a tangible products formation. Two acridine unit products polymerised afterward forming a dimer as a result of an intramolecular coupling. A determinable intermediate has been observed through a spectroscopic test and confirmed by Michaelis–Menten’s plot. Based on Taube’s inorganic electron transfer reaction, an inner-sphere mechanistic pathway is implicated with a stable intermediate complex formation as shown below;

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“…Hexacyanoferrate(III) (HCF) has been widely used to oxidize various organic and inorganic compounds in basic, acidic, and neutral medium . HCF is one electron oxidant with a redox potential of +0.45V for the [Fe(CN) 6 ] −3 /[Fe(CN) 6 ] −4 couple in alkaline medium leading to its reduction to hexacyanoferrate(II), a stable product . In most of the oxidations, HCF is mainly used as a hydrogen atom abstractor and free radical generator .…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Ciprofloxacin by Hexacyanoferrate(III) in the Presence of Cu(II) as a Catalyst: A Kinetic Study

Tazwar¹,

Jain²,

Mittal³

et al. 2017

Int. J. Chem. Kinet.

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The Cu(II)‐catalyzed oxidation of ciprofloxacin (CIP) by hexacyanoferrate(III) (HCF) has been investigated spectrophotometrically in an aqueous alkaline medium at 40°C. The stoichiometry for the reaction indicates that the oxidation of 1 mol of CIP requires 2 mol of HCF. The reaction exhibited first‐order kinetics with respect to [HCF] and less than unit order with respect to [CIP] and [OH−]. The products were also identified on the basis of stoichiometric results and confirmed by the characterization results of LC‐MS and FT‐IR analysis. All the possible reactive species of the reactants have been discussed, and a most probable kinetic model has been envisaged. The activation parameters with respect to the slow step of the mechanism were computed, and thermodynamic quantities were also determined.

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Kinetics and Mechanism of Oxidation of L‐Cystine by Hexacyanoferrate(III) in Alkaline Medium

Cited by 19 publications

References 15 publications

A mediated turnip tissue paper-based amperometric hydrogen peroxide biosensor

A mediated turnip tissue paper-based amperometric hydrogen peroxide biosensor

Thermodynamics and Kinetic Investigation of Reaction of Acriflavine with L-cysteine in Aqueous Medium

Oxidation of Ciprofloxacin by Hexacyanoferrate(III) in the Presence of Cu(II) as a Catalyst: A Kinetic Study

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