Three H2O2 molecules are involved in the "fenton-like" reaction between Co(H2O)6 2+ and H2O2

Ariela Burg; Inna Shusterman; Haya Kornweitz; Dan Meyerstein

doi:10.1039/c4dt00401a

Three H₂O₂ molecules are involved in the "fenton-like" reaction between Co(H₂O)₆ ²⁺ and H₂O₂

Ariela Burg, Inna Shusterman, Haya Kornweitz, Dan Meyerstein

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

35 Scopus citations

Abstract

Co(II) complexes and Co(H₂O)₆²⁺ are used as catalysts in advanced oxidation processes. Therefore it was decided to study the kinetics of reaction of Co(H₂O)₆²⁺ with H₂O₂. Surprisingly, the kinetic results point out that the process involves three consecutive reactions, each of them requiring an H ₂O₂ molecule, i.e. three H₂O₂ molecules ligate to the central cobalt cation prior to the formation of radicals. DFT analysis suggests that the transient (H₂O) ₃Co^II(OOH)₂(H₂O₂) decomposes via: (H₂O)₃Co^II(OOH) ₂(H₂O₂) → (H₂O) ₃Co^II(OOH)(^̇OOH)(OH) + ^̇OH ΔG⁰ = -5.975 kcal mol^-1, with no evidence for the formation of a Co(iii) transient. It is proposed that analogous mechanisms are involved whenever the redox potential of the central cation is too high to enable the reaction: M(H₂O)₆ⁿ⁺ + H ₂O₂ → M⁽ⁿ⁺¹⁾⁺_aq + ^̇OH + OH^-.

Original language	English
Pages (from-to)	9111-9115
Number of pages	5
Journal	Dalton Transactions
Volume	43
Issue number	24
DOIs	https://doi.org/10.1039/c4dt00401a
State	Published - 28 Jun 2014

ASJC Scopus subject areas

Inorganic Chemistry

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title = "Three H2O2 molecules are involved in the {"}fenton-like{"} reaction between Co(H2O)6 2+ and H2O2",

abstract = "Co(II) complexes and Co(H2O)62+ are used as catalysts in advanced oxidation processes. Therefore it was decided to study the kinetics of reaction of Co(H2O)62+ with H2O2. Surprisingly, the kinetic results point out that the process involves three consecutive reactions, each of them requiring an H 2O2 molecule, i.e. three H2O2 molecules ligate to the central cobalt cation prior to the formation of radicals. DFT analysis suggests that the transient (H2O) 3CoII(OOH)2(H2O2) decomposes via: (H2O)3CoII(OOH) 2(H2O2) → (H2O) 3CoII(OOH){\.(}OOH)(OH) +{\. }OH ΔG0 = -5.975 kcal mol-1, with no evidence for the formation of a Co(iii) transient. It is proposed that analogous mechanisms are involved whenever the redox potential of the central cation is too high to enable the reaction: M(H2O)6n+ + H 2O2 → M(n+1)+aq +{\. }OH + OH-.",

author = "Ariela Burg and Inna Shusterman and Haya Kornweitz and Dan Meyerstein",

year = "2014",

month = jun,

day = "28",

doi = "10.1039/c4dt00401a",

language = "English",

volume = "43",

pages = "9111--9115",

journal = "Dalton Transactions",

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publisher = "Royal Society of Chemistry",

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TY - JOUR

T1 - Three H2O2 molecules are involved in the "fenton-like" reaction between Co(H2O)6 2+ and H2O2

AU - Burg, Ariela

AU - Shusterman, Inna

AU - Kornweitz, Haya

AU - Meyerstein, Dan

PY - 2014/6/28

Y1 - 2014/6/28

N2 - Co(II) complexes and Co(H2O)62+ are used as catalysts in advanced oxidation processes. Therefore it was decided to study the kinetics of reaction of Co(H2O)62+ with H2O2. Surprisingly, the kinetic results point out that the process involves three consecutive reactions, each of them requiring an H 2O2 molecule, i.e. three H2O2 molecules ligate to the central cobalt cation prior to the formation of radicals. DFT analysis suggests that the transient (H2O) 3CoII(OOH)2(H2O2) decomposes via: (H2O)3CoII(OOH) 2(H2O2) → (H2O) 3CoII(OOH)(̇OOH)(OH) + ̇OH ΔG0 = -5.975 kcal mol-1, with no evidence for the formation of a Co(iii) transient. It is proposed that analogous mechanisms are involved whenever the redox potential of the central cation is too high to enable the reaction: M(H2O)6n+ + H 2O2 → M(n+1)+aq + ̇OH + OH-.

AB - Co(II) complexes and Co(H2O)62+ are used as catalysts in advanced oxidation processes. Therefore it was decided to study the kinetics of reaction of Co(H2O)62+ with H2O2. Surprisingly, the kinetic results point out that the process involves three consecutive reactions, each of them requiring an H 2O2 molecule, i.e. three H2O2 molecules ligate to the central cobalt cation prior to the formation of radicals. DFT analysis suggests that the transient (H2O) 3CoII(OOH)2(H2O2) decomposes via: (H2O)3CoII(OOH) 2(H2O2) → (H2O) 3CoII(OOH)(̇OOH)(OH) + ̇OH ΔG0 = -5.975 kcal mol-1, with no evidence for the formation of a Co(iii) transient. It is proposed that analogous mechanisms are involved whenever the redox potential of the central cation is too high to enable the reaction: M(H2O)6n+ + H 2O2 → M(n+1)+aq + ̇OH + OH-.

UR - https://www.scopus.com/pages/publications/84901659690

U2 - 10.1039/c4dt00401a

DO - 10.1039/c4dt00401a

M3 - Article

C2 - 24805267

AN - SCOPUS:84901659690

SN - 1477-9226

VL - 43

SP - 9111

EP - 9115

JO - Dalton Transactions

JF - Dalton Transactions

IS - 24

ER -

Three H₂O₂ molecules are involved in the "fenton-like" reaction between Co(H₂O)₆ ²⁺ and H₂O₂

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