Role of the water of crystallization in the Mössbauer spectra of some low-spin ferric and high-spin ferrous compounds. Its implications in comparative studies

1995 ◽  
Vol 200 (5) ◽  
pp. 443-455 ◽  
Author(s):  
E. Reguera ◽  
J. Fernández-Bertrán
Keyword(s):  
High Spin ◽  
Comparative Studies ◽  
Mössbauer Spectra ◽  
Mossbauer Spectra

scholarly journals On Spin Hamiltonian fits to Mössbauer spectra of high-spin Fe(II) porphyrinate systems

2006 ◽  
Vol 170 (1-3) ◽  
pp. 55-60 ◽  
Author(s):  
Charles E. Schulz ◽  
Chuanjiang Hu ◽  
W. Robert Scheidt
Keyword(s):  
High Spin ◽  
Mössbauer Spectra ◽  
Spin Hamiltonian ◽  
Mossbauer Spectra

Spin fluctuation rates from Mössbauer spectra of high-spin ferrous rubredoxin

1979 ◽  
Vol 69 (5) ◽  
pp. 360-363 ◽  
Author(s):  
H. Winkler ◽  
C. Schulz ◽  
P.G. Debrunner
Keyword(s):  
High Spin ◽  
Mössbauer Spectra ◽  
Spin Fluctuation ◽  
Mossbauer Spectra

scholarly journals Mössbauer studies of adrenodoxin. The mechanism of electron transfer in a hydroxylase iron–sulphur protein

1971 ◽  
Vol 125 (3) ◽  
pp. 849-856 ◽  
Author(s):  
R. Cammack ◽  
K. K. Rao ◽  
D. O. Hall ◽  
C. E. Johnson
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
High Spin ◽  
Mössbauer Spectra ◽  
Adrenal Glands ◽  
Native Protein ◽  
Electron Spin Relaxation ◽  
Mossbauer Spectra ◽  
Small Magnetic Field ◽  
Magnetic Hyperfine Structure

1. Mössbauer spectra were measured of adrenodoxin purified from porcine adrenal glands. They show similarities to the spectra of the plant ferredoxins. All of these proteins contain two atoms of iron and two of inorganic sulphide per molecule, and on reduction accept one electron. 2. As with the plant ferredoxins the adrenodoxin for these measurements was enriched with57Fe by reconstitution of the apo-protein, and subsequently was carefully purified and checked by a number of methods to ensure that it was in the same conformation as the native protein and contained no extraneous iron. 3. The Mössbauer spectra of oxidized adrenodoxin at temperatures from 4.2°K to 197°K show that the iron atoms are probably high-spin Fe3+, and in similar environments, and experience little or no magnetic field from the electrons. 4. Mössbauer spectra of reduced adrenodoxin showed magnetic hyperfine structure at all temperatures from 1.7°K to 244°K, in contrast with the reduced plant ferredoxins, which showed it only at lower temperatures. This is a consequence of a longer electron-spin relaxation time in reduced adrenodoxin. 5. At 4.2°K in a small magnetic field the spectrum of reduced adrenodoxin shows a sixline Zeeman pattern due to Fe3+superimposed upon a combined magnetic and quadrupole spectrum due to Fe2+. 6. In a large magnetic field (30kG) each hyperfine pattern is further split into two. Analysis of these spectra at 4.2°K and 1.7°K shows that the effective fields at the Fe3+and Fe2+nuclei are in opposite directions. This agrees with the proposal, first made for the ferredoxins, that the iron atoms are antiferromagnetically coupled. 7. In accord with the model for the ferredoxins, it is proposed that the oxidized adrenodoxin contains two high-spin Fe3+atoms which are antiferromagnetically coupled; on reduction one iron atom becomes high-spin Fe2+.

The role of iron in the weathering of a climosequence of soils derived from schist

Soil Research ◽  
1991 ◽  
Vol 29 (3) ◽  
pp. 387 ◽  
Author(s):  
LP Aldridge ◽  
GJ Churchman
Keyword(s):  
New Zealand ◽  
Mössbauer Spectra ◽  
Ferric Ions ◽  
Ferrous Ions ◽  
Rock Samples ◽  
Mossbauer Spectra ◽  
Muscovite Mica ◽  
Primary Minerals ◽  
Close Parallel

Mossbauer spectra were obtained of the whole soil and clay fractions and some of the sand fractions, as well as some rock samples that were taken from eight soils forming a climosequence on schist in South Island, New Zealand. They show that the main changes in iron across the sequence involve the oxidation of ferrous ions in muscovite mica and its initial weathering products to ferric ions in these minerals and also in oxyhydroxides. The extremes of weathering in the sequence led to the mobilization of iron from primary minerals in soils at the surface of profiles into oxyhydroxides that were deposited lower down in these profiles. While these changes in iron have occurred alongside the loss of K+ from the interlayers of the micas to form expanded phases, there is not a close parallel between the changes on oxidation and those from the initial loss of interlayer potassium.

scholarly journals Mössbauer spectroscopic studies of the terminal dioxygenase protein of benzene dioxygenase from Pseudomonas putida

1981 ◽  
Vol 195 (1) ◽  
pp. 199-203 ◽  
Author(s):  
P J Geary ◽  
D P E Dickson
Keyword(s):  
Pseudomonas Putida ◽  
High Spin ◽  
Mössbauer Spectra ◽  
Spectroscopic Studies ◽  
Reduced Form ◽  
Plant Type ◽  
Mossbauer Spectra ◽  
Extra Electron

Mössbauer spectra obtained from the terminal dioxygenase protein of the benzene dioxygenase system from Pseudomonas putida show that it contains [2Fe--2S] centres similar to those of the two-iron plant-type ferredoxins. In the oxidized form the two iron atoms within the centre are high-spin ferric but with considerable inequivalence. In the reduced form the centre contains one extra electron, and this is localized on one of the iron atoms, which becomes high-spin ferrous.

On Spin Hamiltonian fits to Mössbauer spectra of high-spin Fe(II) porphyrinate systems

NASSAU 2006 ◽  
2006 ◽  
pp. 55-60
Author(s):  
Charles E. Schulz ◽  
Chuanjiang Hu ◽  
W. Robert Scheidt
Keyword(s):  
High Spin ◽  
Mössbauer Spectra ◽  
Spin Hamiltonian ◽  
Mossbauer Spectra
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