Electron Spin Resonance Studies of Aliphatic Ammonium Ion Radicals in Aqueous Sulfuric Acid Glasses

The reaction of hydrogen atoms with n-butylammonium ions in 6 M sulfuric acid glasses yields a characteristic eight-line e.s.r. spectrum, which is attributable to CH 3 ĊHCH 2 CH 2 NH 3 + . Evidence is drawn from computer simulated spectra and from the spectra of other alkylammonium radicals to account for this spectrum. Qualitative agreement between the simulated and experimental spectra is achieved by assuming that the CH 3 ĊHCH 2 — moiety can adopt a range of conformations and can also undergo torsional motion about the sp 2 carbon – methylene carbon bond. The site of hydrogen abstraction from alkylammonium ions is evidently influenced by both NH 3 + and CH 3 groups; abstraction tends to occur away from the former and adjacent to the latter.