Open AccessElectron Spin Resonance Study of the Self-disproportionation of some Semiquinone Radicals in Solution
Author(s) -
S. K. Wong,
W. Sytnyk,
J. K. S. Wan
Publication year - 1972
Publication title -
canadian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.323
H-Index - 68
eISSN - 1480-3291
pISSN - 0008-4042
DOI - 10.1139/v72-484
Subject(s) - chemistry , semiquinone , disproportionation , radical , photochemistry , photodissociation , electron paramagnetic resonance , radical disproportionation , cidnp , quinone , organic chemistry , nuclear magnetic resonance , catalysis , physics
The photolysis of 1,4-benzoquinone, duroquinone, and 1,4-naphthoquinone in isopropanol and in dioxane leads to the observation of e.s.r. spectra of the corresponding semiquinone radicals. The rates of the self-disproportionation of these radicals were measured by the rotating-sector technique. In the case of 1,4-naphthoquinone, unexpected e.s.r. emission was initially observed by photochemically induced dynamic electron polarization of the semiquinone radicals. Photolysis of anthraquinone in isopropanol gives e.s.r. spectra of the anthrasemiquinone radical anions. Their rate of decay was measured and a mechanism for the decay was suggested. The neutral anthrasemiquinone radical, however, was observed when photolyzed in dioxane.