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ESR, ENDOR and TRIPLE resonance studies on radical reactions of 1,4‐benzoquinone and 1,4‐hydroquinone in alkaline methanol and liquid ammonia
Author(s) -
Joela H.,
Kasa S.,
Mäkelä R.,
Salo E.,
Hann K.
Publication year - 1990
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260280313
Subject(s) - chemistry , hydroquinone , methanol , benzoquinone , ammonia , photochemistry , electron paramagnetic resonance , coupling constant , 1,4 benzoquinone , resonance (particle physics) , nuclear magnetic resonance , quinone , organic chemistry , physics , particle physics
The relative signs and absolute values of the hyperfine coupling constants of different methoxy‐1,4‐benzoquinones were measured by ESR, ENDOR and TRIPLE resonance spectroscopy. Reactions of 1,4‐benzoquinone and 1,4‐hydroquinone with methanol took place in alkaline methanol, giving rise to methoxy‐substituted 1,4‐benzoquinones. The same substitution reaction occurred in a mixture of ammonia and methanol. The reactions depended on temperature and the alkali concentration. Coupling constants were assigned by the modified additivity relationship method. An extremely small line width of 0.014 G was measured in the ESR spectrum of deuterated 2,5‐dimethoxy‐1,4‐benzoquinone.