Stable Subporphyrin meso-Aminyl Radicals without Resonance Stabilization by a Neighboring Heteroatom |
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Authors: | Daiki Shimizu Prof. Dr. Ko Furukawa Prof. Dr. Atsuhiro Osuka |
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Affiliation: | 1. Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan;2. Center for Instrumental Analysis, Niigata University, Nishi-ku, Niigata, 950-2181 Japan |
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Abstract: | 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 Cmeso−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. |
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Keywords: | aminyl radicals ESR spectroscopy porphyrinoids stable radicals subporphyrins |
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