Oxidised metallophenolicporphyrins as models for compound I of the peroxidases. Reduction of oxidised iron(III), nickel(II) and zinc(II) complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)prophyrin by the peroxidase substrate p-cresol

N N DAEID, K B NOLAN

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3 Citations (Scopus)

Abstract

Oxidised metal complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (3), M-TBHPP(ox), react with peroxidase substrates such as p-cresol regenerating the parent metalloporphyrins cleanly and quantitatively. The kinetics of the reduction of the oxidised iron(III), nickel(II) and zinc(II) porphyrin complexes in chloroform and methanol have been investigated. Generally rate expressions of the form, rate={k1+k2[p-cresol]}[M-TBHPP(ox)] were observed where the k1 term represents an auto- or solvent-assisted reduction pathway while the k2 term represents a reduction pathway involving p-cresol. For the reduction of Ni-TBHPP(ox) in chloroform however a rate expression of the form rate={k1+k3[p-cresol]2}[Ni-TBHPP(ox)] was observed, the second order dependence of rate on p-cresol concentration being attributed to pre-equilibrium formation of a p-cresol dimer which in the rate determining step is the active reductant. Rate constants for the above reactions are reported as well as activation parameters for the reduction of the oxidised nickel(II) complex in both solvents.

LanguageEnglish
Pages55-60
Number of pages6
JournalInorganica Chimica Acta
Volume211
Issue number1
DOIs
Publication statusPublished - 1 Sep 1993

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Peroxidases
cresols
Nickel
Peroxidase
Zinc
Iron
zinc
nickel
iron
Substrates
Porphyrins
Chlorine compounds
Chloroform
chloroform
porphyrins
Metalloporphyrins
Metal complexes
Dimers
Coordination Complexes
Reducing Agents

Keywords

  • facile aerial oxidation
  • porphyrin
  • cytochrome
  • ligands
  • metals

Cite this

@article{9d772585212945e88f3057cbaab872fa,
title = "Oxidised metallophenolicporphyrins as models for compound I of the peroxidases. Reduction of oxidised iron(III), nickel(II) and zinc(II) complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)prophyrin by the peroxidase substrate p-cresol",
abstract = "Oxidised metal complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (3), M-TBHPP(ox), react with peroxidase substrates such as p-cresol regenerating the parent metalloporphyrins cleanly and quantitatively. The kinetics of the reduction of the oxidised iron(III), nickel(II) and zinc(II) porphyrin complexes in chloroform and methanol have been investigated. Generally rate expressions of the form, rate={k1+k2[p-cresol]}[M-TBHPP(ox)] were observed where the k1 term represents an auto- or solvent-assisted reduction pathway while the k2 term represents a reduction pathway involving p-cresol. For the reduction of Ni-TBHPP(ox) in chloroform however a rate expression of the form rate={k1+k3[p-cresol]2}[Ni-TBHPP(ox)] was observed, the second order dependence of rate on p-cresol concentration being attributed to pre-equilibrium formation of a p-cresol dimer which in the rate determining step is the active reductant. Rate constants for the above reactions are reported as well as activation parameters for the reduction of the oxidised nickel(II) complex in both solvents.",
keywords = "facile aerial oxidation, porphyrin, cytochrome, ligands, metals",
author = "DAEID, {N N} and NOLAN, {K B}",
year = "1993",
month = "9",
day = "1",
doi = "10.1016/S0020-1693(00)82843-1",
language = "English",
volume = "211",
pages = "55--60",
journal = "Inorganica Chimica Acta",
issn = "0020-1693",
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TY - JOUR

T1 - Oxidised metallophenolicporphyrins as models for compound I of the peroxidases. Reduction of oxidised iron(III), nickel(II) and zinc(II) complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)prophyrin by the peroxidase substrate p-cresol

AU - DAEID, N N

AU - NOLAN, K B

PY - 1993/9/1

Y1 - 1993/9/1

N2 - Oxidised metal complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (3), M-TBHPP(ox), react with peroxidase substrates such as p-cresol regenerating the parent metalloporphyrins cleanly and quantitatively. The kinetics of the reduction of the oxidised iron(III), nickel(II) and zinc(II) porphyrin complexes in chloroform and methanol have been investigated. Generally rate expressions of the form, rate={k1+k2[p-cresol]}[M-TBHPP(ox)] were observed where the k1 term represents an auto- or solvent-assisted reduction pathway while the k2 term represents a reduction pathway involving p-cresol. For the reduction of Ni-TBHPP(ox) in chloroform however a rate expression of the form rate={k1+k3[p-cresol]2}[Ni-TBHPP(ox)] was observed, the second order dependence of rate on p-cresol concentration being attributed to pre-equilibrium formation of a p-cresol dimer which in the rate determining step is the active reductant. Rate constants for the above reactions are reported as well as activation parameters for the reduction of the oxidised nickel(II) complex in both solvents.

AB - Oxidised metal complexes of meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (3), M-TBHPP(ox), react with peroxidase substrates such as p-cresol regenerating the parent metalloporphyrins cleanly and quantitatively. The kinetics of the reduction of the oxidised iron(III), nickel(II) and zinc(II) porphyrin complexes in chloroform and methanol have been investigated. Generally rate expressions of the form, rate={k1+k2[p-cresol]}[M-TBHPP(ox)] were observed where the k1 term represents an auto- or solvent-assisted reduction pathway while the k2 term represents a reduction pathway involving p-cresol. For the reduction of Ni-TBHPP(ox) in chloroform however a rate expression of the form rate={k1+k3[p-cresol]2}[Ni-TBHPP(ox)] was observed, the second order dependence of rate on p-cresol concentration being attributed to pre-equilibrium formation of a p-cresol dimer which in the rate determining step is the active reductant. Rate constants for the above reactions are reported as well as activation parameters for the reduction of the oxidised nickel(II) complex in both solvents.

KW - facile aerial oxidation

KW - porphyrin

KW - cytochrome

KW - ligands

KW - metals

U2 - 10.1016/S0020-1693(00)82843-1

DO - 10.1016/S0020-1693(00)82843-1

M3 - Article

VL - 211

SP - 55

EP - 60

JO - Inorganica Chimica Acta

T2 - Inorganica Chimica Acta

JF - Inorganica Chimica Acta

SN - 0020-1693

IS - 1

ER -