EPR spectra and structures of spin-variable iron(III) complexes

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.

Download Full-text

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.

Download Full-text

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.

Download Full-text

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

Download Full-text

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.

Download Full-text

Spectrum Decomposition through Maximum Likelihood Common Factor Analysis of the EPR Spectra of Na+ Containing Carbonated Apatites Dried at 400°C

Calcified Tissue International ◽

10.1007/bf03549785 ◽

1993 ◽

Vol 53 (6) ◽

pp. 416-423

Author(s):

Peter D. W. Moens ◽

Ronald M. H. Verbeeck ◽

Paul J. De Volder ◽

Freddy J. Callens ◽

Erna A. P. De Maeyer

Keyword(s):

Factor Analysis ◽

Maximum Likelihood ◽

Common Factor ◽

Epr Spectra ◽

Common Factor Analysis ◽

Carbonated Apatites ◽

Spectrum Decomposition

Download Full-text

Multiple low spin forms of the cytochrome c ferrihemochrome. EPR spectra of various eukaryotic and prokaryotic cytochromes c.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)32756-4 ◽

1977 ◽

Vol 252 (2) ◽

pp. 574-582 ◽

Cited By ~ 4

Author(s):

D L Brautigan ◽

B A Feinberg ◽

B M Hoffman ◽

E Margoliash ◽

J Preisach ◽

...

Keyword(s):

Cytochrome C ◽

Epr Spectra ◽

Cytochromes C

Download Full-text

The Microscopic Structure Of Shallow Donors In Silicon Carbide

MRS Proceedings ◽

10.1557/proc-442-619 ◽

1996 ◽

Vol 442 ◽

Author(s):

J.-M. Spaeth ◽

S. Greulich-Weber ◽

M. März ◽

E. N. Kalabukhova ◽

S. N. Lukin

Keyword(s):

High Temperature ◽

Low Temperature ◽

Temperature Dependence ◽

Double Resonance ◽

Epr Spectra ◽

Electron Nuclear Double Resonance ◽

Paramagnetic Resonance ◽

Vacancy Pair ◽

Temperature Spectra ◽

Electron Paramagnetic

AbstractThe electronic structure of nitrogen donors in 6H-, 4H- and 3C-SiC is investigated by measuring the nitrogen hyperfine (hf) interactions with electron nuclear double resonance (ENDOR) and the temperature dependence of the hf split electron paramagnetic resonance (EPR) spectra. Superhyperfine (shf) interactions with many shells of 13C and 29Si were measured in 6H-SiC. The hf and shf interactions are discussed in the framework of effective mass theory. The temperature dependence is explained with the thermal occupation of the lowest valley-orbit split A1 and E states. It is proposed that the EPR spectra of P donors observed previously in neutron transmuted 6H-SiC at low temperature (<10K) and high temperature (>60K) are all due to substitutional P donors on the two quasi-cubic and hexagonal Si sites, whereby at low temperature the E state is occupied and at high temperature the A1 state. The low temperature spectra are thus thought not to be due to P-vacancy pair defects as proposed previously.

Download Full-text