Effect of rotational diffusion on the exchange broadening of EPR spectra

<div> <div> <div> <p>The zero- and double-quantum methyl TROSY Hahn-echo and the methyl <sup>1</sup>H-<sup>1</sup>H dipole- dipole cross-correlation nuclear magnetic resonance experiments enable estimation of multiple quantum chemical exchange broadening in methyl groups in proteins. The two relaxation rate constants are established to be linearly dependent using molecular dynamics simulations and empirical analysis of experimental data. This relationship allows chemical exchange broadening to be recognized as an increase in the Hahn-echo relaxation rate constant. The approach is illustrated by analyzing relaxation data collected at three temperatures for <i>E. coli </i>ribonuclease HI and by analyzing relaxation data collected for different cofactor and substrate complexes of <i>E. coli </i>AlkB. </p> </div> </div> </div>

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Properties of electrochemically generated primary cationradicals of phenyl- and 2-(4-tolyl)-1,3,4,7-tetramethylisoindoles

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19801669 ◽

1980 ◽

Vol 45 (6) ◽

pp. 1669-1676 ◽

Cited By ~ 3

Author(s):

Pavel Kubáček

Keyword(s):

Electrochemical Oxidation ◽

Spin Polarization ◽

High Spin ◽

Epr Spectroscopy ◽

Half Life ◽

Electrochemical Behaviour ◽

Epr Spectra ◽

Electrochemical Generation ◽

Splitting Constant ◽

Reduced Temperature

The first step of electrochemical oxidation of 2-phenyl- and 2-(4-tolyl)-1,3,4,7-tetramethylisoindoles in anhydrous acetonitrile produces relatively stable cationradicals which have been studied by means of EPR spectroscopy using the method of internal electrochemical generation of radicals under reduced temperature. The same electrochemical behaviour of the both studied derivatives and identical EPR spectra of their cationradicals can be explained within the Huckel MO method. The largest contribution to the magnitude of splitting constant of nitrogen nucleus is due to π-σ-spin polarization of C-N bonds caused by high spin abundance of pz-AO of carbon atoms. Half-life of decomposition of the studied cationradicals is 4 min at -30°C.

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Complexes of copper(II) and nickel(II) with a Schiff base bonded to a polymeric support

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19832021 ◽

1983 ◽

Vol 48 (7) ◽

pp. 2021-2027 ◽

Cited By ~ 9

Author(s):

Eliška Kálalová ◽

Olga Populová ◽

Štěpánka Štokrová ◽

Pavel Stopka

Keyword(s):

Magnetic Properties ◽

Schiff Base ◽

Coordination Sphere ◽

Polymer Matrix ◽

Glycidyl Methacrylate ◽

Epr Spectra ◽

Polymeric Support ◽

Tetrahedral Configuration ◽

Paramagnetic Complexes

Copper(II) and nickel(II) ions were bonded in complexes of salicylideneimine type on a glycidyl methacrylate-ethylenedimethacrylate copolymer. The geometry of the complexes on the polymer was studied by measuring their magnetic properties, EPR spectra, and ultraviolet-visible spectra.Only paramagnetic complexes possessing a pseudo-tetrahedral configuration were found. The effect of the polymer matrix and of the immobility of the bonded Schiff base on the distortion of the coordination sphere of the central ion is discussed.

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EPR spectra and defect states in glasses of the GexS100-x system

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19821787 ◽

1982 ◽

Vol 47 (7) ◽

pp. 1787-1793 ◽

Cited By ~ 3

Author(s):

Miloslav Frumar ◽

Gustáv Plesch ◽

Eva Černošková ◽

Václav Černý ◽

Ladislav Tichý ◽

...

Keyword(s):

Experimental Data ◽

Epr Spectra ◽

Defect States ◽

Composition Region ◽

Active Defect ◽

Temperature Conditions ◽

Defect Centres

Glasses of the GexS100-x system were studied in the region of 30 ⪬ x ⪬ 45. The concept of magnetically active defect centres was employed to account for the EPR spectra of pure samples as well as those doped with silver or iodine, prepared in different temperature conditions. In terms of this concept a consistent interpretation of the experimental data could be given for the composition region applied.

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EPR spectra of water irradiated at 77°K, adsorbed on synthetic zeolites

Journal of Structural Chemistry ◽

10.1007/bf01551262 ◽

1967 ◽

Vol 8 (4) ◽

pp. 621-622

Author(s):

R. I. Zalevskaya ◽

Yu. D. Tsvetkov

Keyword(s):

Epr Spectra ◽

Synthetic Zeolites

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EPR Spectra of Sintered Cd1−xCrxTe Powdered Crystals with Various Cr Content

Materials ◽

10.3390/ma14133449 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3449

Author(s):

Ireneusz Stefaniuk ◽

Werner Obermayr ◽

Volodymyr D. Popovych ◽

Bogumił Cieniek ◽

Iwona Rogalska

Keyword(s):

Curie Temperature ◽

Room Temperature ◽

Integral Intensity ◽

Resonance Field ◽

Epr Spectra ◽

Paramagnetic Resonance ◽

Simple Method ◽

Paramagnetic Curie Temperature ◽

Cr Content ◽

Electron Paramagnetic

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.

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