Document Detail


Photosensitized generation of superoxide radical in aprotic solvents: an EPR and spin trapping study.
MedLine Citation:
PMID:  8282230     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The UV or visible irradiation of pigments such as curcumin, anthralin, benzanthrone, 1,8-dihydroxyanthraquinone, and rose bengal- or eosine-complexes with cationic surfactants in aerated aprotic solvents, such as benzene, toluene, acetone, n-heptane, cyclohexane, in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generates EPR spectra with hyperfine splitting constants (hfsc's) aN = 12.75 G, a beta H = 10.50 G, a gamma H = 1.26 G in toluene, 12.83 G, 10.64 G, 1.24 G in benzene, 12.75 G, 10.19 G, 1.35 G in acetone and 12.54 G, 10.46 G, 1.38 G in n-heptane and cyclohexane. These spectra are similar to those observed when DMPO reacts with 18-crown-6 ether-solubilized KO2 in the respective solvents and suggests that the photoinduced EPR spectra can be safely assigned to the DMPO/superoxide radical adduct (1). A correlation between the hfsc's of 1 and solvent parameters, the solvent acceptor number AN and the Kosower Z value, has been evaluated in terms of its usefulness for the identification of the DMPO/superoxide adduct in organic media.
Authors:
K Reszka; P Bilski; R H Sik; C F Chignell
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Free radical research communications     Volume:  19 Suppl 1     ISSN:  8755-0199     ISO Abbreviation:  Free Radic. Res. Commun.     Publication Date:  1993  
Date Detail:
Created Date:  1994-02-16     Completed Date:  1994-02-16     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  8709453     Medline TA:  Free Radic Res Commun     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  S33-44     Citation Subset:  IM    
Affiliation:
Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina 27709.
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MeSH Terms
Descriptor/Qualifier:
Photochemistry
Solvents
Spin Labels
Superoxides / chemistry*
Chemical
Reg. No./Substance:
0/Solvents; 0/Spin Labels; 11062-77-4/Superoxides

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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