ピペリジンナイトロキサイド ラジカルのESRスペクトル

Piperidinyl-1-oxy and three dicarboximidyl-1-oxy radicals were produced by UV photolysis or oxidation of a corresponding N-hydroxyl amine and N-hydroxyl dicarboximides. Each spectrum gave an evidence for a long range interaction of an unpaired electron with some protons at γ- or δ-position, in spite of different radical types or radical structures. Especially, piperidinyl-1-oxy radical showed a remarkable spectral changes with an interconversion between two chair conformations at -130～+110℃. All dicarboximidyl-1-oxy radicals exhibited no spectral change because of a weak long range interaction, a diacyl planar structure, and no occurrence of ring cleavage under a prolonged UV irradiation.