Kinetic studies on H+-catalyzed aquation and hydrogen peroxide oxidation of tris-asparaginatochromium(III)

Kiersikowska, Emilia; Marai, Hasan; Wrzeszcz, Grzegorz; Kita, Ewa

doi:10.1007/s11243-013-9727-3

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…2b) as observed in other systems [29]. The chromium(V) complex produced spectroscopically is identical to that observed in our previous studies [18,30,31] -. In most cases the reaction rate was determined from absorption data in the UV region (CrO 4 2-generation).…”

Section: Strongly Alkaline Mediasupporting

confidence: 89%

Oxidation in vitro of chromium(III) dietary supplements mer-[Cr(pic)3] and trans(S,S)-[Cr(Cys)2]− by hydrogen peroxide

et al. 2017

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Biological tests performed using 3T3 fibroblasts indicated low cytotoxicities for the complexes mer- -, where pic = picolinate anion and Cys = cysteine. Oxidation of these complexes by hydrogen peroxide was studied in NaOH and NaHCO 3 media. Electronic (UV-Vis) and EPR spectroscopies were used to monitor the reaction course. 3-anion at pH & 8 was followed by EPR spectroscopy. Based on the obtained kinetic and spectroscopic data, mechanisms for the redox transformations of these chromium(III) complexes are proposed.

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Section: Strongly Alkaline Mediasupporting

confidence: 89%

Oxidation in vitro of chromium(III) dietary supplements mer-[Cr(pic)3] and trans(S,S)-[Cr(Cys)2]− by hydrogen peroxide

et al. 2017

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“…The experimental rate expression (1) is analogous to that postulated previously for acid-catalyzed aquation of [Cr(Asn) 2 (H 2 O) 2 ] ? [8]. Therefore, the same mechanism for dissociation of the first Aa ligand from [Cr(Aa) 2 (H 2 O) 2 ] ?…”

Section: Resultsmentioning

confidence: 85%

“…Chromium(III) complexes with glycine and asparagine of the formulae [Cr(Aa) 3 ] and [Cr(Aa) 2 (H 2 O) 2 ] ? were prepared as described in the literature [7,8].…”

Section: Methodsmentioning

confidence: 99%

“…The Fe(III)induced aquation of this complex was followed spectrophotometrically within the visible range, at 323 K for 30 min. The process was performed in a tandem cell similarly as described previously [8]. The reactions were performed in a 1 cm tandem cell at 323 K (in acidic medium) and at 303-323 K (in alkaline medium).…”

Section: Products Of Fe(iiimentioning

confidence: 99%

“…In our previous papers [7,8], studies of the acid-and basecatalyzed aquation of chromium-glycinato and chromiumasparaginato complexes were presented. The aim of the present work was to synthesize analogous chromium(III) complexes with alanine in order to establish structure-reactivity relationships and to draw some general conclusions.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic studies on acid- and base-catalyzed aquation of bis-alaninatochromium(III) and on oxidation of tris- and bis-Aa–chromium(III) complexes (Aa = Gly, Ala, Asn) by H2O2

Kiersikowska

Marai

Mątewska

et al. 2014

Transition Met Chem

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Two aqua derivatives of [Cr(Ala) 3 ] were characterized in solution. Acid-catalyzed aquation of cis-[Cr(Ala) 2 (H 2 O) 2 ] ? leads to inert [Cr(Ala)(H 2 O) 4 ] 2? , whereas base hydrolysis of cis-Cr(Ala) 2 (OH) 2 ]causes dissociation of both the Ala ligands and formation of chromates(III). Kinetics of these processes have been studied spectrophotometrically in both 0.1-1.0 M HClO 4 and 0.2-0.9 M NaOH under firstorder conditions. A linear dependence of the k obs,H on [H ? ] and a small dependence of the (k obs) OH on [OH-] were established. In the proposed mechanism, the rate determining step is Cr-N bond breaking in the reactive form of the substrate, i.e., in the protonated aqua-or dihydroxo complex. The effect of pH on the complex reactivity is discussed. The kinetic results are compared with those determined previously for analogous glycine and asparagine complexes. Additionally, oxidation of tris-and bis-Aa-chromium(III) complexes, where Aa = Gly, Ala or Asn, by hydrogen peroxide in alkaline medium was studied. Two reaction products were detected: thermodynamically stable CrO 4 2and [Cr(O 2) 4 ] 3that under a large excess of hydrogen peroxide is metastable. The rate-limiting stage of this process is an inner sphere twoelectron transfer within the peroxido intermediate.

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Ag(I)‐Catalyzed Chlorination of Linezolid during Water Treatment: Kinetics and Mechanism

Kulkarni

Hanagadakar

Malladi

et al. 2018

Int J of Chemical Kinetics

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The kinetic and mechanistic study of Ag(I)‐catalyzed chlorination of linezolid (LNZ) by free available chlorine (FAC) was investigated at environmentally relevant pH 4.0–9.0. Apparent second‐order rate constants decreased with an increase in pH of the reaction mixture. The apparent second‐order rate constant for uncatalyzed reaction, e.g., k″app = 8.15 dm3 mol−1 s−1 at pH 4.0 and k″app. = 0.076 dm3 mol−1 s−1 at pH 9.0 and 25 ± 0.2°C and for Ag(I) catalyzed reaction total apparent second‐order rate constant, e.g., k″app = 51.50 dm3 mol−1 s−1 at pH 4.0 and k″app. = 1.03 dm3 mol−1 s−1 at pH 9.0 and 25 ± 0.2°C. The Ag(I) catalyst accelerates the reaction of LNZ with FAC by 10‐fold. A mechanism involving electrophilic halogenation has been proposed based on the kinetic data and LC/ESI/MS spectra. The influence of temperature on the rate of reaction was studied; the rate constants were found to increase with an increase in temperature. The thermodynamic activation parameters Ea, ΔH#, ΔS#, and ΔG# were evaluated for the reaction and discussed. The influence of catalyst, initially added product, dielectric constant, and ionic strength on the rate of reaction was also investigated. The monochlorinated substituted product along with degraded one was formed by the reaction of LNZ with FAC.

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Kinetic studies on H+-catalyzed aquation and hydrogen peroxide oxidation of tris-asparaginatochromium(III)

Cited by 6 publications

References 21 publications

Oxidation in vitro of chromium(III) dietary supplements mer-[Cr(pic)3] and trans(S,S)-[Cr(Cys)2]− by hydrogen peroxide

Oxidation in vitro of chromium(III) dietary supplements mer-[Cr(pic)3] and trans(S,S)-[Cr(Cys)2]− by hydrogen peroxide

Kinetic studies on acid- and base-catalyzed aquation of bis-alaninatochromium(III) and on oxidation of tris- and bis-Aa–chromium(III) complexes (Aa = Gly, Ala, Asn) by H2O2

Ag(I)‐Catalyzed Chlorination of Linezolid during Water Treatment: Kinetics and Mechanism

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