Tests for free-radical intermediates in the decarbonylation of aldehydes by tris(triphenylphosphine)chlororhodium(I)

1980 ◽  
Vol 45 (2) ◽  
pp. 315-318 ◽  
Author(s):  
J. A. Kampmeier ◽  
S. H. Harris ◽  
D. K. Wedegaertner
Keyword(s):  
Free Radical ◽  
Radical Intermediates

A novel probe for free-radical intermediates

1987 ◽  
pp. 1238 ◽  
Author(s):  
Amanda Johns ◽  
John A. Murphy ◽  
Christopher W. Patterson ◽  
Nicholas F. Wooster
Keyword(s):  
Free Radical ◽  
Radical Intermediates

scholarly journals Gas phase formation of phenalene via 10π-aromatic, resonantly stabilized free radical intermediates

2020 ◽  
Vol 22 (27) ◽  
pp. 15381-15388
Author(s):  
Long Zhao ◽  
Ralf I. Kaiser ◽  
Wenchao Lu ◽  
Musahid Ahmed ◽  
Artem D. Oleinikov ◽  
...  
Keyword(s):  
High Temperature ◽  
Free Radical ◽  
Gas Phase ◽  
Phase Formation ◽  
Radical Intermediates ◽  
Temperature Conditions ◽  
Combustion Systems ◽  
Circumstellar Environments

1H-Phenalene can be synthesized via the reaction of the 1-naphthyl radical with methylacetylene and allene under high temperature conditions prevalent in carbon-rich circumstellar environments and combustion systems.

Glutathione Peroxidase-Like Activity of Simple Selenium Compounds. Peroxides and the Heterocyclic N-Oxide Resazurin Acting as O-Atom Donors

1995 ◽  
Vol 50 (3-4) ◽  
pp. 209-219 ◽  
Author(s):  
Walter A. Prtitz
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Glutathione Peroxidase ◽  
Crystal Violet ◽  
The Other ◽  
Atom Transfer ◽  
Selenium Compounds ◽  
Radical Intermediates ◽  
Leuco Crystal Violet ◽  
Acid Pathway

Selenite and selenocystamine [(CyaSe)2] efficiently activate the decomposition of H2O2 y GSH and by other thiols, as demonstrated using a leuco crystal violet POD-based H2O2 assay which is applicable (unlike other assays) also in presence of thiols. The GPx-like activities were estimated to be 3.6 and 2.7 μmol H2O2/min per μmol SeO32- and (CyaSe)2, respectively. Both selenium compounds also activate reduction of the heterocyclic N-oxide resazurin (RN→O) to resorufin (RN) by GSH; H2O2 competes with reduction of this dye. GSSeH and CyaSeH, formed by interaction of GSH with SeO32- and (CyaSe)2, respectively, are likely to be the active reductants. CyaSeH, generated γ-radiolytically from (CyaSe)2, exhibits an absorption peak at 243 nm and is removed by H2O2 with a rate constant of 9.7x102 ᴍ-1 s-1, and slightly slower by hydroperoxides. We have no evidence for one-electron interactions between GSSeH or CyaSeH and H2O2, with formation of free radical intermediates, as previously proposed in the case of selenium-activated reduction of cytochrome c by GSH (Levander et al., Biochemistry 23, 4591-4595 (1973)). Our results can be explained by O-atom transfer from the substrate to the active selenol group. RSeH + H2O2 (RN→O)→RSeOH + H2O (RN), and recycling of RSeOH to RSeH (+ H2O) by GSH, analogous to the selenenic acid pathway of GPx. The substrate specificity appears to be different, however, in that GPx is unable to catalyse RN→O reduction, and GSSeH hardly catalyses the decomposition of cumene- or t-butyl-hydroperoxide; CyaSeH, on the other hand, is active also with the hydroperoxides. RN→O is reduced to RN also by certain oxidizing free radicals, e.g. by the thiyl CyaS·; O -atom transfer may in this case lead to the generation of reactive oxyl radicals.

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