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Stable Subporphyrin meso ‐Aminyl Radicals without Resonance Stabilization by a Neighboring Heteroatom
Author(s) -
Shimizu Daiki,
Furukawa Ko,
Osuka Atsuhiro
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201703097
Subject(s) - radical , heteroatom , chemistry , delocalized electron , steric effects , electron paramagnetic resonance , photochemistry , resonance (particle physics) , stereochemistry , nuclear magnetic resonance , ring (chemistry) , atomic physics , organic chemistry , physics
Most aminyl radicals studied so far are resonance‐stabilized by neighboring heteroatoms, and those without such stabilization are usually short‐lived. We report herein that subporphyrin meso ‐2,4,6‐trichlorophenylaminyl radicals and a bis(5‐subporphyrinyl)aminyl radical are fairly stable under ambient conditions without such stabilization. The subporphyrin meso ‐2,4,6‐trichlorophenylaminyl radical crystal structure displays a characteristically short C meso −N bond and a perpendicular arrangement of the meso ‐arylamino group. The stabilities of these radicals have been ascribed to extensive spin delocalization over the subporphyrin π‐electronic network as well as steric protection around the aminyl radical center.