Résumé | The NMR spectrum of di-tert-butyliminoxy shows that all 18 protons are magnetically equivalent and yields +0.61 G for the electron-proton hyperfine coupling, aH. Positive spin density at the tert-butyl protons contrasts with the negative spin density found in di-tert-butyl nitroxide. The EPR spectrum of the iminoxy at temperatures of -50° and below can be analyzed in terms of two groups of nine protons having aH = +0.481 (probably the anti tert-butyl protons) and +0.772 G (probably the syn protons). At a temperature of 70°, the EPR spectrum can be analyzed in terms of 18 equivalent protons. At intermediate temperatures, theoretical EPR spectra calculated for mutual exchange of syn and anti tert-butyl groups did not fit the experimental spectra. The EPR and NMR spectra of di-(1-adamantyl)iminoxy are also reported. |
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