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EPR study of pyrrolyl‐1‐oxyl and 3‐pyrrolinyl‐1‐oxyl radicals
Author(s) -
Crayston Joe A.,
Kakouris Costas,
Walton John C.
Publication year - 1992
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.1260300115
Subject(s) - chemistry , electron paramagnetic resonance , delocalized electron , unpaired electron , radical , hyperfine structure , hydrogen atom abstraction , spin density , spectroscopy , deuterium , photochemistry , computational chemistry , crystallography , nuclear magnetic resonance , organic chemistry , atomic physics , condensed matter physics , physics , quantum mechanics
Pyrrolyl‐1‐oxyl, 3‐phenylpyrrolyl‐1‐oxyl and a number of deuterium‐substituted derivatives were generated by hydrogen abstraction from the corresponding N ‐hydroxypyrroles, and observed by EPR spectroscopy. They were all transient with lifetimes ≤ 10 −2 s. The hyperfine splittings showed that unpaired spin was delocalized around the five‐membered ring with significant density at N‐1, C‐3 and C‐4, but very low density at C‐2 and C‐5. N ‐Hydroxpyrrole and pyrrolyl‐1‐oxyl were studied by the semi‐empirical AM1 method, and the radical by the INDO method. The transient pyrrolinyl‐1‐oxyl was also generated from the corresponding N ‐hydroxypyrroline and observed by EPR spectroscopy.