Structural, Mössbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting

Emile L. Bominaar, Xiao Qi Ding, Abbasher Gismelseed, Eckhard Bill, Heiner Winkler, Alfred X. Trautwein, Habib Nasri, Jean Fischer, Raymond Weiss

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

The ferrous and ferric form of a ("picket-fence" porphyrinato)(acetato)iron complex, [FeII/IIICH3CO2)(TPPivP)] -,0, were synthesized and characterized by UV-visible, 1H NMR, EPR, and Mössbauer spectroscopy. The structure of the ferrous complex was determined by X-ray diffraction. Crystal data at -100°C: [FeII(CH3CO2)(TPpivP)][NaC222]·C 6H5Cl (C90H108N10O12· NaClFe); monoclinic; a = 18.040 (5), b = 21.521 (5), c = 22.605 (5) Å; β = 100.37 (5)°; Z = 4, Dcalc = 1.259 g cm3; space group P21/n. The five-coordinate iron atom is bonded to four porphyrinato nitrogens 〈Fe-Np〉 = 2.107 (14) Å and to an oxygen atom of the acetate ion (Fe-Oacetate = 2.034 (3) Å), placed inside the molecular cavity of the picket-fence porphyrin. Mössbauer spectra were recorded in the two oxidation states of the complex at temperatures varying from 1.5 to 200 K in fields of 0-6.21 T. The ferrous complex has a large quadrupole splitting, ΔEQ = 4.25 mm s-1, nearly independent of temperature. In the ferric species, the quadrupole splitting, ΔEQ = 1.1 mm s-1, is as normally found in ferric high-spin iron porphyrins. The spin-Hamiltonian analysis of the spectra yields the zero-field parameters D = -0.9 cm-1 and E/D = 0.33 and the magnetic hyperfine parameters Ax,y = -17 T and Az = -13.3 T in the ferrous complex (spin S = 2) and D = 7.5 cm-1, E/D ≈ 0 and Ax,y,z = -20 T in the ferric species (S = 5/2). The values of the zero-field parameters of the ferric species are confirmed by EPR analysis; the g values are gx = 1.960, gy = 2.017, and gz = 2.00. The zero-field splittings and effective g values in the ferric complex are interpreted in terms of a crystal-field model. Theoretical estimates of the quadrupole splitting and zero-field parameters in the ferrous complex are given on the basis of molecular-orbital calculations. The relation between the zero-field tensor (D) and electronic and X-ray structure in the ferrous species is discussed.

Original languageEnglish
Pages (from-to)1845-1854
Number of pages10
JournalInorganic Chemistry
Volume31
Issue number10
Publication statusPublished - 1992

Fingerprint

Heme
Paramagnetic resonance
Fences
Iron
quadrupoles
Porphyrins
fences
Oxidation
oxidation
iron
porphyrins
Hamiltonians
Orbital calculations
Atoms
Crystals
Molecular orbitals
Tensors
Acetates
Nitrogen
Nuclear magnetic resonance

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

Structural, Mössbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting. / Bominaar, Emile L.; Ding, Xiao Qi; Gismelseed, Abbasher; Bill, Eckhard; Winkler, Heiner; Trautwein, Alfred X.; Nasri, Habib; Fischer, Jean; Weiss, Raymond.

In: Inorganic Chemistry, Vol. 31, No. 10, 1992, p. 1845-1854.

Research output: Contribution to journalArticle

Bominaar, Emile L. ; Ding, Xiao Qi ; Gismelseed, Abbasher ; Bill, Eckhard ; Winkler, Heiner ; Trautwein, Alfred X. ; Nasri, Habib ; Fischer, Jean ; Weiss, Raymond. / Structural, Mössbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting. In: Inorganic Chemistry. 1992 ; Vol. 31, No. 10. pp. 1845-1854.
@article{b636f0b558084bf5b0a6134a0ee52011,
title = "Structural, M{\"o}ssbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting",
abstract = "The ferrous and ferric form of a ({"}picket-fence{"} porphyrinato)(acetato)iron complex, [FeII/IIICH3CO2)(TPPivP)] -,0, were synthesized and characterized by UV-visible, 1H NMR, EPR, and M{\"o}ssbauer spectroscopy. The structure of the ferrous complex was determined by X-ray diffraction. Crystal data at -100°C: [FeII(CH3CO2)(TPpivP)][NaC222]·C 6H5Cl (C90H108N10O12· NaClFe); monoclinic; a = 18.040 (5), b = 21.521 (5), c = 22.605 (5) {\AA}; β = 100.37 (5)°; Z = 4, Dcalc = 1.259 g cm3; space group P21/n. The five-coordinate iron atom is bonded to four porphyrinato nitrogens 〈Fe-Np〉 = 2.107 (14) {\AA} and to an oxygen atom of the acetate ion (Fe-Oacetate = 2.034 (3) {\AA}), placed inside the molecular cavity of the picket-fence porphyrin. M{\"o}ssbauer spectra were recorded in the two oxidation states of the complex at temperatures varying from 1.5 to 200 K in fields of 0-6.21 T. The ferrous complex has a large quadrupole splitting, ΔEQ = 4.25 mm s-1, nearly independent of temperature. In the ferric species, the quadrupole splitting, ΔEQ = 1.1 mm s-1, is as normally found in ferric high-spin iron porphyrins. The spin-Hamiltonian analysis of the spectra yields the zero-field parameters D = -0.9 cm-1 and E/D = 0.33 and the magnetic hyperfine parameters Ax,y = -17 T and Az = -13.3 T in the ferrous complex (spin S = 2) and D = 7.5 cm-1, E/D ≈ 0 and Ax,y,z = -20 T in the ferric species (S = 5/2). The values of the zero-field parameters of the ferric species are confirmed by EPR analysis; the g values are gx = 1.960, gy = 2.017, and gz = 2.00. The zero-field splittings and effective g values in the ferric complex are interpreted in terms of a crystal-field model. Theoretical estimates of the quadrupole splitting and zero-field parameters in the ferrous complex are given on the basis of molecular-orbital calculations. The relation between the zero-field tensor (D) and electronic and X-ray structure in the ferrous species is discussed.",
author = "Bominaar, {Emile L.} and Ding, {Xiao Qi} and Abbasher Gismelseed and Eckhard Bill and Heiner Winkler and Trautwein, {Alfred X.} and Habib Nasri and Jean Fischer and Raymond Weiss",
year = "1992",
language = "English",
volume = "31",
pages = "1845--1854",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - Structural, Mössbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting

AU - Bominaar, Emile L.

AU - Ding, Xiao Qi

AU - Gismelseed, Abbasher

AU - Bill, Eckhard

AU - Winkler, Heiner

AU - Trautwein, Alfred X.

AU - Nasri, Habib

AU - Fischer, Jean

AU - Weiss, Raymond

PY - 1992

Y1 - 1992

N2 - The ferrous and ferric form of a ("picket-fence" porphyrinato)(acetato)iron complex, [FeII/IIICH3CO2)(TPPivP)] -,0, were synthesized and characterized by UV-visible, 1H NMR, EPR, and Mössbauer spectroscopy. The structure of the ferrous complex was determined by X-ray diffraction. Crystal data at -100°C: [FeII(CH3CO2)(TPpivP)][NaC222]·C 6H5Cl (C90H108N10O12· NaClFe); monoclinic; a = 18.040 (5), b = 21.521 (5), c = 22.605 (5) Å; β = 100.37 (5)°; Z = 4, Dcalc = 1.259 g cm3; space group P21/n. The five-coordinate iron atom is bonded to four porphyrinato nitrogens 〈Fe-Np〉 = 2.107 (14) Å and to an oxygen atom of the acetate ion (Fe-Oacetate = 2.034 (3) Å), placed inside the molecular cavity of the picket-fence porphyrin. Mössbauer spectra were recorded in the two oxidation states of the complex at temperatures varying from 1.5 to 200 K in fields of 0-6.21 T. The ferrous complex has a large quadrupole splitting, ΔEQ = 4.25 mm s-1, nearly independent of temperature. In the ferric species, the quadrupole splitting, ΔEQ = 1.1 mm s-1, is as normally found in ferric high-spin iron porphyrins. The spin-Hamiltonian analysis of the spectra yields the zero-field parameters D = -0.9 cm-1 and E/D = 0.33 and the magnetic hyperfine parameters Ax,y = -17 T and Az = -13.3 T in the ferrous complex (spin S = 2) and D = 7.5 cm-1, E/D ≈ 0 and Ax,y,z = -20 T in the ferric species (S = 5/2). The values of the zero-field parameters of the ferric species are confirmed by EPR analysis; the g values are gx = 1.960, gy = 2.017, and gz = 2.00. The zero-field splittings and effective g values in the ferric complex are interpreted in terms of a crystal-field model. Theoretical estimates of the quadrupole splitting and zero-field parameters in the ferrous complex are given on the basis of molecular-orbital calculations. The relation between the zero-field tensor (D) and electronic and X-ray structure in the ferrous species is discussed.

AB - The ferrous and ferric form of a ("picket-fence" porphyrinato)(acetato)iron complex, [FeII/IIICH3CO2)(TPPivP)] -,0, were synthesized and characterized by UV-visible, 1H NMR, EPR, and Mössbauer spectroscopy. The structure of the ferrous complex was determined by X-ray diffraction. Crystal data at -100°C: [FeII(CH3CO2)(TPpivP)][NaC222]·C 6H5Cl (C90H108N10O12· NaClFe); monoclinic; a = 18.040 (5), b = 21.521 (5), c = 22.605 (5) Å; β = 100.37 (5)°; Z = 4, Dcalc = 1.259 g cm3; space group P21/n. The five-coordinate iron atom is bonded to four porphyrinato nitrogens 〈Fe-Np〉 = 2.107 (14) Å and to an oxygen atom of the acetate ion (Fe-Oacetate = 2.034 (3) Å), placed inside the molecular cavity of the picket-fence porphyrin. Mössbauer spectra were recorded in the two oxidation states of the complex at temperatures varying from 1.5 to 200 K in fields of 0-6.21 T. The ferrous complex has a large quadrupole splitting, ΔEQ = 4.25 mm s-1, nearly independent of temperature. In the ferric species, the quadrupole splitting, ΔEQ = 1.1 mm s-1, is as normally found in ferric high-spin iron porphyrins. The spin-Hamiltonian analysis of the spectra yields the zero-field parameters D = -0.9 cm-1 and E/D = 0.33 and the magnetic hyperfine parameters Ax,y = -17 T and Az = -13.3 T in the ferrous complex (spin S = 2) and D = 7.5 cm-1, E/D ≈ 0 and Ax,y,z = -20 T in the ferric species (S = 5/2). The values of the zero-field parameters of the ferric species are confirmed by EPR analysis; the g values are gx = 1.960, gy = 2.017, and gz = 2.00. The zero-field splittings and effective g values in the ferric complex are interpreted in terms of a crystal-field model. Theoretical estimates of the quadrupole splitting and zero-field parameters in the ferrous complex are given on the basis of molecular-orbital calculations. The relation between the zero-field tensor (D) and electronic and X-ray structure in the ferrous species is discussed.

UR - http://www.scopus.com/inward/record.url?scp=33751391993&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33751391993&partnerID=8YFLogxK

M3 - Article

VL - 31

SP - 1845

EP - 1854

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 10

ER -