Komplexe des Cu(I), Ag(I) und Rh(III) mit Nitronylnitroxylradikalliganden/Complexes of Cu(I), Ag(I) and Rh(III) with Nitronylnitroxylradicals as Ligands

1983 ◽  
Vol 38 (2) ◽  
pp. 265-268 ◽  
Author(s):  
Astrid Dorfer ◽  
Karl E. Schwarzhans
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Metal Ions ◽  
Intramolecular Interaction ◽  
Magnetic Moments ◽  
Epr Spectra ◽  
Temperature Dependent ◽  
Stable Free Radical ◽  
Unpaired Electrons ◽  
Meta Isomer

Abstract The stable free radical 4,4,5,5-tetramethyl-imidazoline-1-oxyl-2-p-pyridyl-3-oxide (L1) has been prepared and used as a ligand in copper (I), silver(I) and rhodium(III) complexes, the meta isomer (L2) as a ligand in a rhodium(III) complex, too. The magnetic moments and the EPR spectra of the free radicals and the complexes have been investigated. A solvent and temperature dependent intramolecular interaction between the radicalic ligands was found in the silver(I) complex, but in none of the complexes any intramolecular interaction between the metal ions and the unpaired electrons of the ligands could be observed.

scholarly journals Notizen: Nitroxylradikal-Metallkomplexe / Nitroxyl Radical Metal Complexes

1976 ◽  
Vol 31 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Rudolf Weissgerber ◽  
Karl E. Schwarzhans
Keyword(s):  
Free Radicals ◽  
Metal Ions ◽  
Metal Complexes ◽  
Nitroxyl Radical ◽  
Magnetic Moments ◽  
Epr Spectra ◽  
Temperature Dependent ◽  
Stable Free Radicals ◽  
Dependent Interaction

A series of complexes formed between metal ions and the stable free radicals 3-carboxy-2,2,5,5-tetramethylpyrroline-1-oxyl, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl and glyoxal-bis(2,2,6,6-tetramethyl-4-iminopiperidine-1-oxyl) has been prepared. The magnetic moments and the EPR spectra of the complexes and the free ligands have been investigated. Some of the complexes show a temperature dependent interaction between the radicalic groups of the ligands.

Metallkomplexe mit paramagnetischen Salicylaldimin- und Thiosemicarbazon-Liganden / Metal Complexes of Paramagnetic Salicylaldimine and Thiosemicarbazone Ligands

1971 ◽  
Vol 26 (12) ◽  
pp. 1210-1215 ◽  
Author(s):  
Dieter Jahr ◽  
Karl E. Schwarzhans ◽  
Dietrich Nöthe ◽  
Paul K. Burkert
Keyword(s):  
Free Radicals ◽  
Metal Complexes ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Epr Spectra ◽  
Temperature Dependent ◽  
Unpaired Electrons ◽  
Stable Free Radicals ◽  
Dependent Interaction

A series of complexes formed between metals and the stable free radicals 2,2,6,6-tetramethylpiperidine-1-oxyl-4- (N-salicylaldimine) and 2,2,6,6-tetramethylpiperidone (4) -1-oxyl-thiosemicarba-zone has been prepared. The magnetic moments and the epr spectra of the complexes have been investigated. Some of the complexes show a temperature dependent interaction between the radicalic nitroxyl groups of the ligands. No interaction was found, however, between the metal ion and the unpaired electrons of the ligands.

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.

Metallkomplexe mit paramagnetischen Derivaten des Piperidin-1-oxyls / Metal Complexes of Paramagnetic Derivatives of Piperidine-1-oxyl

1973 ◽  
Vol 28 (1-2) ◽  
pp. 55-62 ◽  
Author(s):  
Dieter Jahr ◽  
Karl Heinz Rebhan ◽  
Karl E. Schwarzhans ◽  
Josef Wiedemann
Keyword(s):  
Free Radicals ◽  
Solid State ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Transition Metal Ions ◽  
Epr Spectra ◽  
Temperature Dependent ◽  
Derivatives Of ◽  
Stable Free Radicals ◽  
Dependent Interaction

A series of complexes formed between transition metal ions and the stable free radicals 2,2,6,6- tetramethyl-4-amino-4-caboxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-aminopiperidine-l -oxyl, 2,2,6,6-tetram ethyl-piperidine-l-oxyl and glyoxal-bis(2,2,2,6,6-tetramethyl-4-iminopiperidine-1- oxyl) has been prepared. The magnetic moments and the epr-spectra of the complexes have been investigated. Some of the complexes show a temperature dependent interaction between the radicalic nitroxyl groups of the ligands. By analysis of the epr-spectra in the solid state there was found in some cases an interaction between the metal ion and the unpaired electrons of the ligands.

scholarly journals Studies on Stable Free Radicals. V Reactivity of a Stable Free Radical, 2,2,6,6-Tetramethyl-4-oxopiperidine-1-oxyl

1971 ◽  
Vol 44 (8) ◽  
pp. 2207-2210 ◽  
Author(s):  
Takao Yoshioka ◽  
Susumu Higashida ◽  
Syoji Morimura ◽  
Keisuke Murayama
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Stable Free Radical ◽  
Stable Free Radicals

Involvement of free radicals in the oxidative degradation of indole-3-acetic acid

1969 ◽  
Vol 47 (2) ◽  
pp. 220-224 ◽  
Author(s):  
E. V. Parups
Keyword(s):  
Acetic Acid ◽  
Free Radicals ◽  
Free Radical ◽  
Oxidative Degradation ◽  
Breakdown Product ◽  
Stable Free Radical ◽  
Indole 3 Acetic Acid

The enzymic or nonenzymic oxidation of indole-3-acetic acid (IAA) was promoted in the presence of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The involvement of DPPH with the IAA free-radicals in the nonenzymic and the peroxidase-catalyzed oxidations was discussed. Methylene-oxindole was identified as a breakdown product of IAA, indicating a pathway operative with this radical.

scholarly journals THE PREPARATION AND SOME REACTION OF 2,2-DIPHENYL-1-(3,6-DINITR0-4-COUMARINYL) HYDRAZYL FREE RADICAL

1998 ◽  
Vol 6 (7) ◽  
pp. 59-66
Author(s):  
Petre Ionita ◽  
Marcela Rovinaru ◽  
Ovidiu Maior
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Crown Ether ◽  
Potassium Permanganate ◽  
1H Nmr ◽  
Sodium Nitrite ◽  
Nitrous Acid ◽  
Lead Dioxide ◽  
Epr Spectra ◽  
New Compounds

The new persistent 2,2-diphenyl-1-(3,6-dinitro-4-coumarinyl)hydrazyl free radical 4 was obtained by potassium permanganate or lead dioxide oxidation of the corresponding 2,2-diphenyl-1-(3,6-dinitro-4-coumarinyl)hydrazine 3; hydrazine 3 reacts with nitrous acid to give successively the 2-(p-nitrophenyl)-2-phenyl-1-(3,6-dinitro-4-coumarinyl) hydrazine 6 and 2,2-(p-nitrophenyl)-1-(3,6-dinitro-4-coumarinyl) hydrazine 7. Compound 6 results also from free radical 4 and sodium nitrite in the presence of 15-C-5 crown ether. The structure of new compounds was confirmed by means of TLC, UV-Vis, 1H-NMR, IR, and for the free radicals by the EPR spectra.

Free Radicals Generated in Photocatalytic Oxidation of Some Amines and Diamines

1996 ◽  
Vol 1 (2) ◽  
Author(s):  
Ciping Chen ◽  
Daohui Lu ◽  
Guangzhi Xu
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Photocatalytic Oxidation ◽  
Spin Trapping ◽  
Experimental Results ◽  
Epr Spectra ◽  
Radical Species ◽  
Radical Intermediates ◽  
Radical Adduct ◽  
Spin Trapping Technique

AbstractFree radical intermediates produced during photocatalytic oxidation of some typical amines and diamines were investigated by a spin trapping technique. The EPR spectra of N-centered radical adduct and Ccentered radical adduct were observed. Experimental results disclose that these radicals are participants in the initial steps of photodegradation of these compounds. A mechanism which is consistent with the observation of these radical species is discussed.

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.

scholarly journals Effect of microwave power on EPR spectra of thermally sterilized eucerinum anhydricum

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 439-442 ◽  
Author(s):  
Paweł Ramos ◽  
Piotr Pepliński ◽  
Barbara Pilawa
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Microwave Power ◽  
Spin Lattice Relaxation ◽  
Epr Spectra ◽  
Relaxation Processes ◽  
Spin Lattice ◽  
Radical Concentration ◽  
Free Radical Concentration ◽  
Thermal Sterilization

Abstract Free radicals formed during thermal sterilization of eucerinum anhydricum – the pharmaceutical base were examined by an X-band (9.3 GHz) spectrometer. Eucerinum anhydricum was sterilized at different physical conditions according to the Polish Pharmacopeia norms. The samples were heated at temperatures: 160°C (120 min), 170°C (60 min), and 180°C (30 min). The aim of this study is to compare free radical concentration and effect of microwave power on EPR spectra of eucerinum anhydricum base thermally sterilized at different temperatures and periods of time. The effect of time storage on the free radicals in the heated samples was tested. Free radical concentrations in the sample stored 15 min strongly decreased with the increasing of sterilization temperature, probably as the result of recombination. Storage caused strong decrease of free radical concentrations in the samples, probably as the result of interactions with oxygen. It was observed to be independent of sterilization conditions from 2 days of storage and longer. Because of the lowest free radical concentration, for eucerinum anhydricum thermal sterilization at 180°C for 30 min is recommended. The sterilized samples should be stored at inert atmosphere without oxygen molecules. Fast spin-lattice relaxation processes existed in sterilized eucerinum anhydricum. The character of changes of amplitudes and linewidths of EPR lines with increasing of microwave power was the same for different storage times. The parameters of thermal sterilization and storage time influenced free radical concentration in eucerinum anhydricum, but magnetic spin-lattice interactions were unchanged. The usefulness of EPR spectroscopy in optimization of thermal sterilization process of eucerinum anhydricum was confirmed.

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