A novel iron-enhanced pathway for base-catalyzed catechol oxidation by dioxygen

Zoltán May, László I. Simándi, A. Vértes

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The kinetics and mechanisms of the catecholase-type biomimetic activation of O2 by the new dioximatoiron(II) complexes [Fe(Hdmed)]+, [Fe(Hdmpd)]+ and [Fe(H2dmdt)]2+ have been studied in methanol. Kinetic measurements reveal first order behavior with respect to catalyst and O2 and a saturation type dependence on the 3,5-di-tert-butylcatechol (H2dtbc) substrate. Added triethylamine increases the rate by changing the reaction mechanism. An important, hitherto unknown feature is iron(II)-enhanced base catalysis of H2dtbc oxidation, via coordination of HdtbcO2 - to the Fe(II) complex present, resulting in a significant acceleration of oxidation. A mechanism involving free radicals is suggested on grounds of ESR evidence. The activity pattern of the catalyst complexes correlates with coordination number and symmetry as revealed by Mössbauer spectra.

Original languageEnglish
Pages (from-to)349-358
Number of pages10
JournalReaction Kinetics and Catalysis Letters
Volume89
Issue number2
DOIs
Publication statusPublished - Aug 2006

Fingerprint

Iron
Oxygen
iron
Oxidation
oxidation
catalysts
Catalysts
Kinetics
biomimetics
kinetics
Biomimetics
Free radicals
coordination number
free radicals
Catalysis
catalysis
Free Radicals
Paramagnetic resonance
Methanol
methyl alcohol

Keywords

  • Biomimetic catalysis
  • Catechol oxidation
  • Dioximatoiron(II)
  • Mössbauer spectra
  • Oxidation kinetics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Catalysis

Cite this

A novel iron-enhanced pathway for base-catalyzed catechol oxidation by dioxygen. / May, Zoltán; Simándi, László I.; Vértes, A.

In: Reaction Kinetics and Catalysis Letters, Vol. 89, No. 2, 08.2006, p. 349-358.

Research output: Contribution to journalArticle

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N2 - The kinetics and mechanisms of the catecholase-type biomimetic activation of O2 by the new dioximatoiron(II) complexes [Fe(Hdmed)]+, [Fe(Hdmpd)]+ and [Fe(H2dmdt)]2+ have been studied in methanol. Kinetic measurements reveal first order behavior with respect to catalyst and O2 and a saturation type dependence on the 3,5-di-tert-butylcatechol (H2dtbc) substrate. Added triethylamine increases the rate by changing the reaction mechanism. An important, hitherto unknown feature is iron(II)-enhanced base catalysis of H2dtbc oxidation, via coordination of HdtbcO2 - to the Fe(II) complex present, resulting in a significant acceleration of oxidation. A mechanism involving free radicals is suggested on grounds of ESR evidence. The activity pattern of the catalyst complexes correlates with coordination number and symmetry as revealed by Mössbauer spectra.

AB - The kinetics and mechanisms of the catecholase-type biomimetic activation of O2 by the new dioximatoiron(II) complexes [Fe(Hdmed)]+, [Fe(Hdmpd)]+ and [Fe(H2dmdt)]2+ have been studied in methanol. Kinetic measurements reveal first order behavior with respect to catalyst and O2 and a saturation type dependence on the 3,5-di-tert-butylcatechol (H2dtbc) substrate. Added triethylamine increases the rate by changing the reaction mechanism. An important, hitherto unknown feature is iron(II)-enhanced base catalysis of H2dtbc oxidation, via coordination of HdtbcO2 - to the Fe(II) complex present, resulting in a significant acceleration of oxidation. A mechanism involving free radicals is suggested on grounds of ESR evidence. The activity pattern of the catalyst complexes correlates with coordination number and symmetry as revealed by Mössbauer spectra.

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