Some Metal Complexes as Free Radicals for Polarized Targets

1991 ◽  
pp. 344-346
Author(s):  
N. Nakasuka
Keyword(s):  
Free Radicals ◽  
Metal Complexes ◽  
Polarized Targets

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.

Metal complexes as antioxidants. 9. Application of the spin scavenging technique to the reaction of transition metal dialkyldithiophosphates and dialkyldithiocarbamates with tertiary alkyl hydroperoxides

1982 ◽  
Vol 60 (2) ◽  
pp. 224-228 ◽  
Author(s):  
J. A. Howard ◽  
T. Yamada
Keyword(s):  
Free Radicals ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Zero Order ◽  
Radical Scavengers ◽  
Homolytic Reaction ◽  
Alkyl Hydroperoxides ◽  
Low Concentrations ◽  
Tertiary Alkyl

The spin scavenging technique has been applied to the initial homolytic reaction between tertiary alkyl hydroperoxides and zinc and nickel complexes of dialkyldithiophosphoric acids and dialkyldithiocarbamic acids using low concentrations of Galvinoxyl and 2,2,6,6-tetramethyl-4-oxo-1-piperidinyloxyl as radical scavengers. This method has demonstrated that these transition metal complexes react with hydroperoxides at 303 K to generate free-radicals. Quantitative kinetic data have been obtained from zero-order scavenger decays and the efficiency with which the transition metal complexes generate free-radicals increases in the order Zn[R2NCS2]2 < Zn[(RO)2PS2]2 < Ni[(RO)2PS2]2 < Ni[R2NCS2]2. Deviations from zero-order scavenger decay have been observed, particularly at high complex concentrations, and have been attributed to reaction of the complex with transient radicals to give products which do not react rapidly with the scavenger.

scholarly journals RADICAL INITIATED COPOLYMERIZATION OF METHYL METHACRYLATE AND ACRYLONITRILE IN PRESENCE OF IRON COMPLEXES

2021 ◽  
Vol 64 (4) ◽  
pp. 34-41
Author(s):  
Ruslan R. Galimullin ◽  
Natalya N. Sigaeva ◽  
Sergey V. Kolesov
Keyword(s):  
Free Radicals ◽  
Nmr Spectroscopy ◽  
Methyl Methacrylate ◽  
Metal Complexes ◽  
1H Nmr Spectroscopy ◽  
Initial Rate ◽  
Iron Complexes ◽  
Active Centers ◽  
Iron Metal ◽  
Effective Constants

This article represents data on the effect of organometallic iron complexes: ferrocene, dicarbonyl dimer of cyclopentadienyl iron and tricarbonyl cyclooctatetraene iron on the copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) initiated by benzoyl peroxide. It is shown that the introduction of metal complexes and their structure affect the initial rate of copolymerization, the form of the diagrams of the composition of the obtained copolymers, and the values of the effective constants of the relative activities of the comonomers in the copolymerization of methyl methacrylate and acrylonitrile (system metallocomplex of iron – peroxide benzoyl: ferrocene – peroxide benzoyl: rММА = 1.58; rАН= 0.08 in 60 °С; rММА = 1.30; rАН = 0.05 in 50 °С; dicarbonyl dimer cyclopentadienyl iron–peroxide benzoyl: rММА = 1.36; rАН = 0.06 in 60 °С; rММА = 1.09; rАН = 0.14 in 50 °С; tricarbonyl cyclooctatetraene iron -peroxide benzoyl: rММА = 1.08; rАН = 0.15 in 60 °С; rММА = 1.14; rАН = 0.05 in 50 °С; peroxide benzoyl: rММА = 1.11; rАН = 0.07 in 60 °С; rММА = 1.11; rАН = 0.07 in 50 °С). The proportions of triadic sequences of units in copolymers, experimentally determined from 1H NMR spectroscopy, are given, as well as the calculated proportions of dyads. The presence of iron metal complexes affects the distribution of the proportions of the triad and dyad sequences of units, as well as their microstructure in copolymers. These changes are explained by the formation of macromolecules, both with the participation of free radicals and the stereospecific coordination active centers of polymerization that are formed in the presence of iron complexes.

Mass spectra of metal complexes with stable imidazoline free radicals

1985 ◽  
Vol 34 (7) ◽  
pp. 1523-1525
Author(s):  
K. M. Indrichan ◽  
S. V. Larionov ◽  
N. V. G�rb�l�u ◽  
V. I. Ovcharenko
Keyword(s):  
Free Radicals ◽  
Metal Complexes ◽  
Mass Spectra

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.

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