Functional mimic of dioxygen-activating centers in non-heme diiron enzymes: Mechanistic implications of paramagnetic intermediates in the reactions between diiron(II) complexes and dioxygen

Dongwhan Lee, Brad Pierce, Carsten Krebs, Michael P. Hendrich, Boi Hanh Huynh, Stephen J. Lippard

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

Two tetracarboxylate diiron(II) complexes, [Fe2(μ-O2CArTol)2 (O2CArTol)2 (C5H5N)2] (1a) and [Fe2μ-O2CArTol)4 (4-tBuC5H4N)2] (2a), where ArTolCO2- = 2,6-di(p-tolyl)benzoate, react with 02 in CH2Cl2 at -78°C to afford dark green intermediates 1b (λmax ≅ 660 nm; ε = 1600 M-1 cm-1) and 2b λmax ≅ 670 nm; ε = 1700 M-1 cm-1), respectively. Upon warming to room temperature, the solutions turn yellow, ultimately converting to isolable diiron(III) compounds [Fe2(μ-OH)2(μ-02CArTol) 2(O2CArTol)2L2] (L = C5H5N (1c), 4-tBuC5H4N (2c)). EPR and Mössbauer spectroscopic studies revealed the presence of equimolar amounts of valence-delocalized FeIIFeIII and valence-trapped FeIIIFeIV species as major components of solution 2b. The spectroscopic and reactivity properties of the FeIIIFeIV species are similar to those of the intermediate X in the RNR-R2 catalytic cycle. EPR kinetic studies revealed that the processes leading to the formation of these two distinctive paramagnetic components are coupled to one another. A mechanism for this reaction is proposed and compared with those of other synthetic and biological systems, in which electron transfer occurs from a low-valent starting material to putative high-valent dioxygen adduct(s).

Original languageEnglish (US)
Pages (from-to)3993-4007
Number of pages15
JournalJournal of the American Chemical Society
Volume124
Issue number15
DOIs
StatePublished - Apr 17 2002

Fingerprint

Paramagnetic resonance
Enzymes
Oxygen
Benzoates
Biological systems
Electrons
Kinetics
Temperature

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

@article{201a82011ce64486b761591a7fb4e3ef,
title = "Functional mimic of dioxygen-activating centers in non-heme diiron enzymes: Mechanistic implications of paramagnetic intermediates in the reactions between diiron(II) complexes and dioxygen",
abstract = "Two tetracarboxylate diiron(II) complexes, [Fe2(μ-O2CArTol)2 (O2CArTol)2 (C5H5N)2] (1a) and [Fe2μ-O2CArTol)4 (4-tBuC5H4N)2] (2a), where ArTolCO2- = 2,6-di(p-tolyl)benzoate, react with 02 in CH2Cl2 at -78°C to afford dark green intermediates 1b (λmax ≅ 660 nm; ε = 1600 M-1 cm-1) and 2b λmax ≅ 670 nm; ε = 1700 M-1 cm-1), respectively. Upon warming to room temperature, the solutions turn yellow, ultimately converting to isolable diiron(III) compounds [Fe2(μ-OH)2(μ-02CArTol) 2(O2CArTol)2L2] (L = C5H5N (1c), 4-tBuC5H4N (2c)). EPR and M{\"o}ssbauer spectroscopic studies revealed the presence of equimolar amounts of valence-delocalized FeIIFeIII and valence-trapped FeIIIFeIV species as major components of solution 2b. The spectroscopic and reactivity properties of the FeIIIFeIV species are similar to those of the intermediate X in the RNR-R2 catalytic cycle. EPR kinetic studies revealed that the processes leading to the formation of these two distinctive paramagnetic components are coupled to one another. A mechanism for this reaction is proposed and compared with those of other synthetic and biological systems, in which electron transfer occurs from a low-valent starting material to putative high-valent dioxygen adduct(s).",
author = "Dongwhan Lee and Brad Pierce and Carsten Krebs and Hendrich, {Michael P.} and Huynh, {Boi Hanh} and Lippard, {Stephen J.}",
year = "2002",
month = "4",
day = "17",
doi = "10.1021/ja012251t",
language = "English (US)",
volume = "124",
pages = "3993--4007",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "15",

}

Functional mimic of dioxygen-activating centers in non-heme diiron enzymes : Mechanistic implications of paramagnetic intermediates in the reactions between diiron(II) complexes and dioxygen. / Lee, Dongwhan; Pierce, Brad; Krebs, Carsten; Hendrich, Michael P.; Huynh, Boi Hanh; Lippard, Stephen J.

In: Journal of the American Chemical Society, Vol. 124, No. 15, 17.04.2002, p. 3993-4007.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Functional mimic of dioxygen-activating centers in non-heme diiron enzymes

T2 - Mechanistic implications of paramagnetic intermediates in the reactions between diiron(II) complexes and dioxygen

AU - Lee, Dongwhan

AU - Pierce, Brad

AU - Krebs, Carsten

AU - Hendrich, Michael P.

AU - Huynh, Boi Hanh

AU - Lippard, Stephen J.

PY - 2002/4/17

Y1 - 2002/4/17

N2 - Two tetracarboxylate diiron(II) complexes, [Fe2(μ-O2CArTol)2 (O2CArTol)2 (C5H5N)2] (1a) and [Fe2μ-O2CArTol)4 (4-tBuC5H4N)2] (2a), where ArTolCO2- = 2,6-di(p-tolyl)benzoate, react with 02 in CH2Cl2 at -78°C to afford dark green intermediates 1b (λmax ≅ 660 nm; ε = 1600 M-1 cm-1) and 2b λmax ≅ 670 nm; ε = 1700 M-1 cm-1), respectively. Upon warming to room temperature, the solutions turn yellow, ultimately converting to isolable diiron(III) compounds [Fe2(μ-OH)2(μ-02CArTol) 2(O2CArTol)2L2] (L = C5H5N (1c), 4-tBuC5H4N (2c)). EPR and Mössbauer spectroscopic studies revealed the presence of equimolar amounts of valence-delocalized FeIIFeIII and valence-trapped FeIIIFeIV species as major components of solution 2b. The spectroscopic and reactivity properties of the FeIIIFeIV species are similar to those of the intermediate X in the RNR-R2 catalytic cycle. EPR kinetic studies revealed that the processes leading to the formation of these two distinctive paramagnetic components are coupled to one another. A mechanism for this reaction is proposed and compared with those of other synthetic and biological systems, in which electron transfer occurs from a low-valent starting material to putative high-valent dioxygen adduct(s).

AB - Two tetracarboxylate diiron(II) complexes, [Fe2(μ-O2CArTol)2 (O2CArTol)2 (C5H5N)2] (1a) and [Fe2μ-O2CArTol)4 (4-tBuC5H4N)2] (2a), where ArTolCO2- = 2,6-di(p-tolyl)benzoate, react with 02 in CH2Cl2 at -78°C to afford dark green intermediates 1b (λmax ≅ 660 nm; ε = 1600 M-1 cm-1) and 2b λmax ≅ 670 nm; ε = 1700 M-1 cm-1), respectively. Upon warming to room temperature, the solutions turn yellow, ultimately converting to isolable diiron(III) compounds [Fe2(μ-OH)2(μ-02CArTol) 2(O2CArTol)2L2] (L = C5H5N (1c), 4-tBuC5H4N (2c)). EPR and Mössbauer spectroscopic studies revealed the presence of equimolar amounts of valence-delocalized FeIIFeIII and valence-trapped FeIIIFeIV species as major components of solution 2b. The spectroscopic and reactivity properties of the FeIIIFeIV species are similar to those of the intermediate X in the RNR-R2 catalytic cycle. EPR kinetic studies revealed that the processes leading to the formation of these two distinctive paramagnetic components are coupled to one another. A mechanism for this reaction is proposed and compared with those of other synthetic and biological systems, in which electron transfer occurs from a low-valent starting material to putative high-valent dioxygen adduct(s).

UR - http://www.scopus.com/inward/record.url?scp=0037123244&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037123244&partnerID=8YFLogxK

U2 - 10.1021/ja012251t

DO - 10.1021/ja012251t

M3 - Article

C2 - 11942838

AN - SCOPUS:0037123244

VL - 124

SP - 3993

EP - 4007

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 15

ER -