Isotropic proton hyperfine coupling constants of two cationic nitroxides

Abstract

The isotropic proton hyperfine coupling constants of 2,2,6,6-tetramethylpiperidineoxide–trimethylammonium bromide and 2,2,6,6-tetramethylpiperidineoxide–dodecyldimethylammonium bromide have been determined using a nuclear magnetic resonance technique. The measured coupling constants have been used to generate computer simulated electron paramagnetic resonance (e.p.r.) spectra, which show moderate agreement with experimental e.p.r. spectra. Evidence is presented which indicates that intermolecular exchange effects in the e.p.r. spectra may account for the discrepancies.