scholarly journals ESR and Magnetic Susceptibility Studies on High-Spin Tetrahedral Cobalt(II)–Thiolate Complexes: An Approach to Rubredoxin-Type Active Sites

1991 ◽  
Vol 64 (4) ◽  
pp. 1205-1212 ◽  
Author(s):  
Kouichi Fukui ◽  
Hiroaki Ohya-Nishiguchi ◽  
Noboru Hirota
Keyword(s):  
Magnetic Susceptibility ◽  
High Spin ◽  
Active Sites ◽  
Thiolate Complexes

scholarly journals NEXAFS–Spectra and Magnetic Susceptibility of Nickel and Chromium Doped of Bismuth Niobate

2020 ◽  
pp. 340-348
Author(s):  
Irina E. Vasilyeva ◽  
Sergey V. Nekipelov ◽  
Boris A. Makeev ◽  
Alexey G. Krasnov ◽  
Nadezhda A. Zhuk
Keyword(s):  
Magnetic Susceptibility ◽  
Charge State ◽  
Electronic State ◽  
High Spin ◽  
Solid Solutions ◽  
Exchange Interactions ◽  
High Spin State ◽  
Chromium Oxides ◽  
X Ray ◽  
Nexafs Spectroscopy

The electronic state and character of exchange interactions of nickel and chromium atoms in solid solutions of Bi5Nb3-3xМ3xO15-δ (М-Cr,Ni) was researched by methods of magnetic susceptibility and NEXAFS-spectroscopy. NEXAFS spectra of nickel and chromium oxides were obtained. According to X-ray spectroscopy in solid solutions, chromium atoms are mainly in the charge state of Cr(III), and nickel atoms in the high-spin state of Ni(II) in octahedral coordination. In solid solutions, paramagnetic chromium and nickel atoms are present in the form of monomers and clusters with a common antiferromagnetic type of exchange

scholarly journals Analysis of the visible spectra of some sperm-whale ferrimyoglobin derivatives

1968 ◽  
Vol 110 (2) ◽  
pp. 297-301 ◽  
Author(s):  
D. W. Smith ◽  
R. J. P. Williams
Keyword(s):  
Magnetic Susceptibility ◽  
High Spin ◽  
Linear Correlation ◽  
Near Infrared ◽  
Soret Band ◽  
Sperm Whale ◽  
Spin States ◽  
Infrared Band ◽  
Visible Spectra ◽  
The Relationship

The visible spectra of sperm-whale metmyoglobin and its fluoride, hydroxide, cyanide, azide, cyanate, formate, acetate, thiocyanate and nitrite derivatives were measured and resolved into Gaussian components. A linear correlation between the intensity of the band at 18500cm.−1 and the magnetic susceptibility is found, suggesting that the band is the β-band of the low-spin form. The analysed intensity of this band can be used to determine the relative proportions of the two spin states present. The spectra of the pure high-spin and low-spin components of each derivative can be reconstructed. Correlations between the energy of the near-infrared band and the visible bands of the high-spin form, and between the position and intensity of the 16000cm.−1 band, are demonstrated. The relationship between the position of the Soret band and the magnetic susceptibility can be explained in terms of the equilibrium between spin states.

Mössbauer, magnetic susceptibility, EPR, and EXAFS investigations of the vibrationally-induced low-spin/high-spin transition in a biomimetic Fe(III) complex

1994 ◽  
Vol 90 (1) ◽  
pp. 453-457 ◽  
Author(s):  
Ch. Butzlaff ◽  
E. Bill ◽  
W. Meyer ◽  
H. Winkler ◽  
A. X. Trautwein ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
High Spin ◽  
Spin Transition

Thermodynamics of metal-ligand bond formation. IV. Base adducts of Bis(ethylxanthato)nickel(II) and Bis(dialkyldithiophosphato)nickel(II)

1971 ◽  
Vol 24 (12) ◽  
pp. 2509 ◽  
Author(s):  
DR Dakternieks ◽  
DP Graddon
Keyword(s):  
Magnetic Susceptibility ◽  
High Spin ◽  
Thermodynamic Data ◽  
Benzene Solution ◽  
Bond Formation ◽  
Spin Configuration ◽  
Thermometric Titration ◽  
Metal Ligand ◽  
Ligand Bond

The reactions of pyridine with bis(ethylxanthato)nickel(~~) and bis(dipropy1- dithiophosphato)nickel(~~) and of pyridine, 4-methylpyridine, bipyridyl, and 2,9-dimethyl-l,l0-phenanthroline with bis(diethyldithiophosphato)nickel(~~) have been studied by thermometric titration in benzene solution a t 30�C. The xanthate adds two molecules of pyridine simultaneously, AHolz = -75 kJ mol-1, ASOlz = -186 J K-1 mol-1. With the dithiophosphates, two molecules of base are added in distinct steps; the enthalpy of addition of bipyridyl is similar to that of two molecules of pyridine, but the enthalpy of addition of 2,9-dimethyl-l,l0- phenanthroline is much smaller. The thermodynamic data obtained for these reactions are as follows (AH" in k J mol-1, AS0 in J K-1 mol-1) : dipropyldithiophosphate with py AHol -71, AS01 -211, AHoz 4-2, AS0$ +34 diethyldithiophosphate PY -73 -218 +4 + 40 diethyldithiophosphate 4-mepy - 83 -248 + 7 + 59 diethyldithiophosphate bipy -76 diethyldithiophosphate Mesphen -47 Determination of the magnetic susceptibility in benzene solution containing varying pyridine concentrations has shown that base adducts of the dithiophosphates of both the types NiLzB and NiLzBz have the metal atom in the high-spin configuration.

Nonlinear magnetic susceptibility of molecular magnets: Tunneling of high-spin molecules

1997 ◽  
Vol 56 (1) ◽  
pp. 75-78 ◽  
Author(s):  
N. Vernier ◽  
G. Bellessa ◽  
T. Mallah ◽  
M. Verdaguer
Keyword(s):  
Magnetic Susceptibility ◽  
High Spin ◽  
Molecular Magnets

Spectroscopic studies on two-iron ferredoxins

1974 ◽  
Vol 7 (4) ◽  
pp. 443-504 ◽  
Author(s):  
R. H. Sands ◽  
W. R. Dunham
Keyword(s):  
High Spin ◽  
Active Site ◽  
Active Sites ◽  
Spectroscopic Studies ◽  
Transport Proteins ◽  
Distorted Tetrahedron ◽  
X Ray ◽  
Iron Proteins ◽  
Electron Transport Proteins ◽  
Reduced State

The application of magnetic resonance techniques to biological systems has permitted a detailed study of the nature of the active sites of many proteins that had not been possible previously. Among these is the whole class of iron—sulphur proteins which have been implicated as electron transport proteins in a variety of fundamental processes: photosynthesis, hydroxylation and nitrogen fixation to name but a few.The single-iron proteins in this class, the rubredoxins, have been studied extensively by chemical, spectroscopic and X-ray crystallographic techniques (Lovenberg, 1973), and the active site is composed of a single iron atom bound in a distorted tetrahedron of cysteine sulphur ligands. The iron is high-spin ferric in the oxidized state and high-spin ferrous in the reduced state. This structure is shown in Fig. I (α).

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