Mechanisms of Reaction Between Co(II) Complexes and Peroxymonosulfate

Shamir, Dror; Zilbermann, Israel; Katsaran, Dmitry; Pochtarenko, Lyudmila; Yardeni, Guy; Burg, Ariela; Albo, Yael; Kornweitz, Haya; Meyerstein, Dan

doi:10.1002/ejic.202100646

Cited by 4 publications

(4 citation statements)

References 25 publications

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“…Hydroxocobalamin hydrochloride (Sigma, St. Louis, MO, USA; HOCbl; ≥96%), Oxone (Sigma; 2KHSO 5 · K 2 SO 4 · KHSO 4 ), terephthalic acid (TA; Sigma-Aldrich, St. Louis, MO, USA; 98%), 2-hydroxyterephthalic acid (J&K), Orange II sodium salt (Sigma-Aldrich; ≥85%) were used without additional purification. The content of KHSO 5 in OXONE was determined by the reported procedure [ 7 ]. Concentrations of Cbl stock solutions were determined using UV-visible spectroscopy via conversion of Cbl to its dicyano-form (extinction coefficient is 30,400 M −1 ∙cm −1 at 368 nm [ 47 ]).…”

Section: Methodsmentioning

confidence: 99%

“…It was suggested that cobalt species act as a Fenton reagent in the reaction with HSO 5 − [ 6 ]. However, the most recent explanation of the mechanism of Co(II)-assisted HSO 5 − activation includes the consequent binding of two SO 5 2− molecules which results in O-O bond labilization in one of SO 5 2− ligands, and the liberation of sulfate radicals [ 7 ]. Another study demonstrates the pronounced oxidizing properties of the Co(II)-SO 5 2− complex as a primary intermediate in the Co(II)/peroxymonosulfate system [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

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Aquacobalamin Accelerates Orange II Destruction by Peroxymonosulfate via the Transient Formation of Secocorrinoid: A Mechanistic Study

Dereven’kov

Sakharova

Osokin

et al. 2022

IJMS

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Besides its use in medicine, vitamin B12 (cobalamin) and its derivatives have found in numerous applications as catalysts. However, studies related to the activation of oxidants via cobalamin are scant. In this work, we showed how the addition of aquacobalamin (H2OCbl) accelerates the destruction of azo-dye Orange II by peroxymonosulfate (HSO5−) in aqueous solutions. In neutral and weakly alkaline media, the process is initiated by the modification of the corrin macrocycle with HSO5−, which requires the preliminary deprotonation of the aqua-ligand in H2OCbl to give hydroxocobalamin, producing 5,6-dioxo-5,6-secocobalamin or its isomer (14,15-dioxo-14,15-secocobalamin). In acidic solutions, where the concentration of hydroxocobalamin is negligible, the formation of dioxo-seco-species is not observed, and the reaction between H2OCbl and HSO5− results in slow chromophore bleaching. Using terephthalic acid, we demonstrated the formation of hydroxyl radicals in the mixture of H2OCbl with HSO5-, whereas the generation of sulfate radicals was proved by comparing the effects of ethanol and nitrobenzene on Orange II destruction using the H2OCbl/HSO5− system. The reaction mechanism includes the binding of HSO5− to the Co(III) ion of dioxo-secocobalamin, which results in its deprotonation and the labilization of the O-O bond, leading to the formation of sulfate and hydroxyl radicals which further react with Orange II.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aquacobalamin Accelerates Orange II Destruction by Peroxymonosulfate via the Transient Formation of Secocorrinoid: A Mechanistic Study

Dereven’kov

Sakharova

Osokin

et al. 2022

IJMS

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“…The reaction of HSO 5 − with Co(H 2 O) 6 2+ and with Co II (P 2 O 7 )(H 2 O) 2 2− require more than one peroxymonosulfate to form radicals [ 46 ].…”

Section: Other Fenton-like Reactionsmentioning

confidence: 99%

What Are the Oxidizing Intermediates in the Fenton and Fenton-like Reactions? A Perspective

Meyerstein

2022

Antioxidants

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The Fenton and Fenton-like reactions are of major importance due to their role as a source of oxidative stress in all living systems and due to their use in advanced oxidation technologies. For many years, there has been a debate whether the reaction of FeII(H2O)62+ with H2O2 yields OH• radicals or FeIV=Oaq. It is now known that this reaction proceeds via the formation of the intermediate complex (H2O)5FeII(O2H)+/(H2O)5FeII(O2H2)2+ that decomposes to form either OH• radicals or FeIV=Oaq, depending on the pH of the medium. The intermediate complex might also directly oxidize a substrate present in the medium. In the presence of FeIIIaq, the complex FeIII(OOH)aq is formed. This complex reacts via FeII(H2O)62+ + FeIII(OOH)aq → FeIV=Oaq + FeIIIaq. In the presence of ligands, the process often observed is Ln(H2O)5−nFeII(O2H) → L•+ + Ln−1FeIIIaq. Thus, in the presence of small concentrations of HCO3− i.e., in biological systems and in advanced oxidation processes—the oxidizing radical formed is CO3•−. It is evident that, in the presence of other transition metal complexes and/or other ligands, other radicals might be formed. In complexes of the type Ln(H2O)5−nMIII/II(O2H−), the peroxide might oxidize the ligand L without oxidizing the central cation M. OH• radicals are evidently not often formed in Fenton or Fenton-like reactions.

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“…invoked a hypothetical aqueous Co(II)–OOSO 3 – complex to explain this observation. The density functional theory-based calculations also proposed the formation of Co(II)–OOSO 3 – complex intermediates during the activation of PMS by aqueous Co(II) . However, both of the aqueous Co(IV)-oxo and Co(II)–OOSO 3 – complexes have been rarely experimentally captured or spectroscopically characterized in the literature.…”

Section: Introductionmentioning

confidence: 99%

Reinvestigation on High-Valent Cobalt for the Degradation of Micropollutants in the Co(II)/Peroxymonosulfate System: Roles of Co(III)

Cao,

Wang,

et al. 2024

Environ. Sci. Technol.

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Recently, reactive cobalt (Co) species, including Co(IV)-oxo and Co(II)-OOSO3 – complexes, were proposed to be the primary intermediates formed during the process of activating peroxymonosulfate (PMS) by Co(II), mainly based on the observation that the methyl phenyl sulfoxide (MPSO) probe was transformed to methyl phenyl sulfone (MPSO2) in this process. However, in this work, we rationalized the results of the MPSO probe assay based on the chemistry of aqueous Co(III), an alternative reactive Co species. Moreover, 18O-labeled water experiments and Raman spectroscopy analysis clearly proved the Co(III) formation in the Co(II)/PMS system. In parallel, sulfate radicals (SO4 •–) and hydroxyl radicals (HO•) were also involved in this system. Further, the relative contribution of Co(III) to the abatement of carbamazepine (CBZ), a representative micropollutant, in the Co(II)/PMS system was significantly increased by increasing the Co(II) dosage but was dramatically decreased by improving the PMS dosage and increasing the pH from 3 to 7. Additionally, the degradation pathway of CBZ by Co(III) and the Co(II)/PMS system was comparatively explored, confirming that Co(III) participated in the hydroxylation, carbonylation, deacetylation, and ring reduction of CBZ by the Co(II)/PMS system. Our work addresses the controversy regarding the reactive Co species involved in the Co(II)/PMS system with evidence of Co(III) as the chief one, which highlights the significance of re-evaluating the relative contribution of Co(III) in relevant environmental decontamination processes.

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Mechanisms of Reaction Between Co(II) Complexes and Peroxymonosulfate

Cited by 4 publications

References 25 publications

Aquacobalamin Accelerates Orange II Destruction by Peroxymonosulfate via the Transient Formation of Secocorrinoid: A Mechanistic Study

Aquacobalamin Accelerates Orange II Destruction by Peroxymonosulfate via the Transient Formation of Secocorrinoid: A Mechanistic Study

What Are the Oxidizing Intermediates in the Fenton and Fenton-like Reactions? A Perspective

Reinvestigation on High-Valent Cobalt for the Degradation of Micropollutants in the Co(II)/Peroxymonosulfate System: Roles of Co(III)

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