Metal-nitroxyl interactions. 52. EPR spectra of nitroxyl radicals coordinated to manganese(III) tetraphenylporphyrin via the nitroxyl oxygen

1987 ◽  
Vol 26 (16) ◽  
pp. 2618-2620 ◽  
Author(s):  
Kundalika M. More ◽  
Gareth R. Eaton ◽  
Sandra S. Eaton
Keyword(s):  
Nitroxyl Radicals ◽  
Epr Spectra

EPR spectra and structure of certain phosphorus-containing nitroxyl radicals

1976 ◽  
Vol 11 (5) ◽  
pp. 515-520 ◽  
Author(s):  
A. V. Il'yasov ◽  
Ya. A. Levin ◽  
A. Sh. Mukhtarov ◽  
M. S. Skorobogatova
Keyword(s):  
Nitroxyl Radicals ◽  
Epr Spectra ◽  
Phosphorus Containing

Shape of the EPR spectra of nitroxyl radicals in solvating mixtures

1977 ◽  
Vol 13 (2) ◽  
pp. 141-145
Author(s):  
L. I. Antsiferova ◽  
N. N. Korst ◽  
A. N. Ivanova ◽  
N. S. Nazemets
Keyword(s):  
Nitroxyl Radicals ◽  
Epr Spectra

Pt(II)-, Pd(II)-und Cu(II)-Komplexe mit dem 4.4.5.5-Tetramethylimidazolin-1-oxyl-2-m-pyridyl-3-oxid-Liganden / Pt(II), Pd(II) and Cu(II) Complexes with the Ligand 4,4,5,5-Tetramethylimidazohne-1-oxyl-2-m-pyridyl-3-oxide

1981 ◽  
Vol 36 (2) ◽  
pp. 195-197 ◽  
Author(s):  
Karl E. Schwarzhans ◽  
Alfons Stuefer
Keyword(s):  
Free Radical ◽  
Magnetic Moments ◽  
Nitroxyl Radicals ◽  
Epr Spectra ◽  
Stable Free Radical

Abstract The stable free radical 4,4,5,5-tetramethylimidazoline-1-oxyl-2-m-pyridyl-3-oxide has been prepared and used as a ligand in platinum(II), palladium(II) and copper(II) complexes. The magnetic moments and the EPR spectra of the complexes and the free radical have been investigated. The complexes show a considerable interaction between the nitroxyl radicals of the ligands.

ChemInform Abstract: EPR SPECTRA AND STRUCTURE OF SOME PHOSPHORUS-CONTAINING NITROXYL RADICALS

1976 ◽  
Vol 7 (4) ◽  
pp. no-no
Author(s):  
A. V. IL'YASOV ◽  
YA. A. LEVIN ◽  
A. SH. MUKHTAROV ◽  
M. S. SKOROBOGATOVA
Keyword(s):  
Nitroxyl Radicals ◽  
Epr Spectra ◽  
Phosphorus Containing

Kupfer(II)-Komplexe mit dia- und paramagnetischen Carboxylatliganden / Copper(II) Complexes with Dia- and Paramagnetic Carboxylate Ligands

1980 ◽  
Vol 35 (1) ◽  
pp. 68-70 ◽  
Author(s):  
Richard Fedrigolli ◽  
Karl E. Schwarzhans
Keyword(s):  
Free Radicals ◽  
Magnetic Moments ◽  
Nitroxyl Radicals ◽  
Epr Spectra ◽  
Carboxylate Ligands ◽  
Cyclohexanecarboxylic Acid ◽  
Stable Free Radicals

Abstract The stable free radicals 4-carboxy-2,2,6,6-tetramethylpiperidinooxyl, 4-carboxy-methylene-2,2,6,6-tetramethylpiperidinooxyl, 4-carboxymethyl-2,2,6,6-tetramethylpipe-ridinooxyl and 3′-carboxy-2,2,6,6-tetramethylpiperidine-4-spiro-2′-oxirane-l-yloxyl have been prepared and used as ligands in copper(II) complexes. The magnetic moments and the EPR spectra of the complexes and the free radicals have been investigated and compared with complexes containing diamagnetic cyclohexanecarboxylic acid or cyclo -hexaneacetic acid ligands. One of the copper(II) complexes shows a considerable inter-action between the nitroxyl radicals of the ligands.

Electron Paramagnetic Resonance as a Probe of Conformational Flexibility in Cyclic Alkanes

1980 ◽  
Vol 34 (3) ◽  
pp. 268-275 ◽  
Author(s):  
Marsha J. Heinig ◽  
G. R. Eaton ◽  
S. S. Eaton
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Long Range ◽  
Hyperfine Coupling ◽  
Nitroxyl Radical ◽  
Nitroxyl Radicals ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Cyclic Alkanes ◽  
Temperature Spectra ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) spectra of a homologous series of nitroxyl radicals derived from cyclic alkanones with 6 to 15 carbons in the ring have been obtained as a function of temperature. Long-range hyperfine coupling (0.7 to 2.2 G) was observed in the low-temperature spectra for rings with 6, 7, and 9 to 15 carbons. Deuteration of the 11- to 14-membered rings indicated that the long-range coupling was to one of the protons on the carbons adjacent to the point of attachment of the nitroxyl radical. For the 9- to 15-membered rings, there was a temperature region in which the hyperfine coupling decreased rapidly. This decrease is attributed to rapid conformational averaging on the EPR time scale. For the 12-, 13-, and 15-membered rings, the high temperature spectra exhibited resolved hyperfine coupling which can be computer-simulated, assuming four equivalent protons. The activation energies estimated from the coalescence temperatures in the EPR spectra fall in the range estimated by nuclear magnetic resonance and show similar influences of ring size on rigidity.

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

1980 ◽  
Vol 45 (6) ◽  
pp. 1669-1676 ◽  
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.

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

1983 ◽  
Vol 48 (7) ◽  
pp. 2021-2027 ◽  
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.

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

1982 ◽  
Vol 47 (7) ◽  
pp. 1787-1793 ◽  
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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