scholarly journals New perspectives for polychlorinated trityl radicals

2021 ◽  
Author(s):  
Imma Ratera ◽  
José Vidal-Gancedo ◽  
Daniel Maspoch ◽  
Stefan T. Bromley ◽  
Nuria Crivillers ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Organic P ◽  
Organic Free Radical ◽  
Unpaired Electrons

An organic free radical is a molecule with one or more unpaired electrons. Although most free radicals are highly reactive, chemists have developed a few families of so-called persistent organic...

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.

Study of antioxidant potential in leaves, stems, nuts of Juglans regia L.

2012 ◽  
Vol 1 (10) ◽  
pp. 79 ◽  
Author(s):  
G. Raja* ◽  
Ivvala Anand Shaker ◽  
Inampudi Sailaja ◽  
R. Swaminathan ◽  
S. Saleem Basha ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Juglans Regia ◽  
Radical Scavenging ◽  
Antioxidant Compounds ◽  
Free Radical Damage ◽  
Radical Damage

Natural antioxidants can protect the human body from free radicals and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods. The role of antioxidants has protected effect against free radical damage that may cause many diseases including cancer. Primary sources of naturally occurring antioxidants are known as whole grains, fruits, and vegetables. Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. The role of antioxidants has attracted much interest with respect to their protective effect against free radical damage that may cause many diseases including cancer. Juglans regia L. (walnut) contains antioxidant compounds, which are thought to contribute to their biological properties. Polyphenols, flavonoids and flavonols concentrations and antioxidant activity of Leaves, Stems and Nuts extract of Juglans regia L. as evaluated using DPPH, ABTS, Nitric acid, hydroxyl and superoxide radical scavenging activity, lipid peroxidation and total oxidation activity were determined. The antioxidant activities of Leaves, Stems and Nuts extract of Juglans regia L. were concentration dependent in different experimental models and it was observed that free radicals were scavenged by the test compounds in all the models.

THE KINETICS OF THE THERMAL REACTIONS OF ETHYLENE OXIDE

1963 ◽  
Vol 41 (12) ◽  
pp. 2956-2961 ◽  
Author(s):  
M. Lynne Neufeld ◽  
Arthur T. Blades
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Ethylene Oxide ◽  
Thermal Reactions ◽  
Kinetics Of

The thermal reactions of ethylene oxide in the presence of an excess of propylene have been studied as a function of pressure and it has been found that there are two sets of products, acetaldehyde and free radicals, presumably methyl and formyl. These products are believed to arise from an excited acetaldehyde intermediate. Some evidence has been obtained for the occurrence of a surface-catalyzed rearrangement to acetaldehyde but the free radical products are uninfluenced by surface.

scholarly journals Mechanistic Insight into Antimicrobial and Antioxidant Potential of Jasminum Species: A Herbal Approach for Disease Management

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1089
Author(s):  
Acharya Balkrishna ◽  
Akansha Rohela ◽  
Abhishek Kumar ◽  
Ashwani Kumar ◽  
Vedpriya Arya ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Drug Resistance ◽  
Free Radicals ◽  
Free Radical ◽  
Microbial Pathogens ◽  
Free Radical Scavengers ◽  
Bioactive Constituents ◽  
Global Issues ◽  
Iridoid Glucosides ◽  
Insight Into

Drug resistance among microbial pathogens and oxidative stress caused by reactive oxygen species are two of the most challenging global issues. Firstly, drug-resistant pathogens cause several fatalities every year. Secondly aging and a variety of diseases, such as cardiovascular disease and cancer, are associated with free radical generated oxidative stress. The treatments currently available are limited, ineffective, or less efficient, so there is an immediate need to tackle these issues by looking for new therapies to resolve resistance and neutralize the harmful effects of free radicals. In the 21st century, the best way to save humans from them could be by using plants as well as their bioactive constituents. In this specific context, Jasminum is a major plant genus that is used in the Ayurvedic system of medicine to treat a variety of ailments. The information in this review was gathered from a variety of sources, including books, websites, and databases such as Science Direct, PubMed, and Google Scholar. In this review, a total of 14 species of Jasminum have been found to be efficient and effective against a wide variety of microbial pathogens. In addition, 14 species were found to be active free radical scavengers. The review is also focused on the disorders related to oxidative stress, and it was concluded that Jasminum grandiflorum and J. sambac normalized various parameters that were elevated by free radical generation. Alkaloids, flavonoids (rutoside), terpenes, phenols, and iridoid glucosides are among the main phytoconstituents found in various Jasminum species. Furthermore, this review also provides insight into the mechanistic basis of drug resistance, the generation of free radicals, and the role of Jasminum plants in combating resistance and neutralizing free radicals.

scholarly journals Covalent Modification of Highly Ordered Pyrolytic Graphite with a Stable Organic Free Radical by Using Diazonium Chemistry

2016 ◽  
Vol 23 (6) ◽  
pp. 1415-1421 ◽  
Author(s):  
Gonca Seber ◽  
Alexander V. Rudnev ◽  
Andrea Droghetti ◽  
Ivan Rungger ◽  
Jaume Veciana ◽  
...  
Keyword(s):  
Free Radical ◽  
Pyrolytic Graphite ◽  
Covalent Modification ◽  
Highly Ordered Pyrolytic Graphite ◽  
Organic Free Radical

Mechanochemical Reactions Leading to Reinforcement in Rubbers

1960 ◽  
Vol 33 (4) ◽  
pp. 929-939
Author(s):  
R. J. Ceresa
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Covalent Bond ◽  
Vinyl Monomers ◽  
Research Association ◽  
Block Copolymerization ◽  
Wide Range ◽  
Carbon Gel ◽  
Internal Mixer ◽  
Mechanochemical Reactions

Abstract The development of the single rotor internal mixer (at the British Rubber Producers' Research Association) has facilitated the research into mechanochemical reactions of a wide range of high polymers. The term “mechanochemical” has been applied to reactions such as mastication, the mechanism of which involves the primary step of mechanical scission of a polymer chain into polymeric free radicals at a carbon to carbon or other covalent bond. The processes which have been studied previously include the cold mastication of rubberlike polymers, the formation of carbon gel, the interpolymerization of two elastomers during blending, and block copolymerization by the cold mastication of polymers plasticized by vinyl monomers. The evidence for the polymeric free radical nature of these reactions has recently been reviewed.

Oxygen free radical-mediated selective endothelial dysfunction in isolated coronary artery

1992 ◽  
Vol 262 (3) ◽  
pp. H806-H812 ◽  
Author(s):  
K. Todoki ◽  
E. Okabe ◽  
T. Kiyose ◽  
T. Sekishita ◽  
H. Ito
Keyword(s):  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Free Radicals ◽  
Free Radical ◽  
Coronary Artery ◽  
Iron Chelator ◽  
Oxygen Free Radical ◽  
Alpha Tocopherol ◽  
Endothelium Dependent Relaxation ◽  
Iron Chelator Deferoxamine

To understand the direct involvement of free radicals causing reduction in endothelium-dependent relaxation of isolated canine coronary ring preparations, this study was undertaken to examine the effect of free radicals generated from dihydroxy fumarate (DHF) plus Fe(3+)-ADP or from H2O2 plus FeSO4. The vasodilators (acetylcholine, bradykinin, A23187, and nitroglycerin) were given after DHF/Fe(3+)-ADP or H2O2/FeSO4 was removed from the organ chamber. The earlier DHF/Fe(3+)-ADP exposure produced an attenuation of the relaxation of the rings induced by acetylcholine, bradykinin, or A23187 but not of the relaxation induced by nitroglycerin. The observed effect of previous DHF/Fe(3+)-ADP exposure was significantly protected in the vessels isolated from the dogs treated with alpha-tocopherol. In the experiments for assessing the effect of various scavengers, 1O2 scavenger histidine or iron chelator deferoxamine effectively protected the attenuation induced by DHF/Fe(3+)-ADP exposure of the relaxation elicited by acetylcholine; superoxide dismutase (SOD), catalase, or dimethyl sulfoxide (DMSO) had no effect on this system. Furthermore, the relaxation elicited by acetylcholine, but not nitroglycerin, was significantly attenuated by the earlier exposure to .OH generated by Fenton's reagent (H2O2+FeSO4); the attenuation was significantly protected by DMSO. These results are consistent with the view that .OH, 1O2, and/or iron-dependent reactive species selectively damage endothelium-dependent relaxation as opposed to endothelium-independent relaxation in endothelium-intact coronary ring preparations. It is also postulated that lipid peroxidation may be responsible for this effect.

The Study of Australian Coal Maturity:  Relationship between Solid-State NMR Aromaticities and Organic Free-Radical Count

2005 ◽  
Vol 19 (3) ◽  
pp. 954-959 ◽  
Author(s):  
Thilanga S. Bandara ◽  
G. S. Kamali Kannangara ◽  
Michael A. Wilson ◽  
Christopher J. Boreham ◽  
Keith Fisher
Keyword(s):  
Free Radical ◽  
Solid State ◽  
Solid State Nmr ◽  
Organic Free Radical ◽  
Australian Coal
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