Generation and reactions of the ammoniumyl radical cation (NH3+˙): an electron spin resonance investigation

Abstract

E.s.r. spectroscopy has been employed to study the reactions of a variety of organic compounds with ammoniumyl (NH₃^+˙) generated in a flow system from the titanium (III)–hydroxylarnine couple. Radicals resulting from hydrogenatom abstraction from certain substrates (e.g. alkanols) have been detected and it is concluded that NH₃^+˙ is an electrophilic species with a greater degree of selectivity than hydroxyl. A pseudo steady-state analysis for radicals in the cavity is shown to be approps late and values have been obtained for the rate constant for the initiating reaction [k(Ti^III+ NH₂OH)ca. 6 × 10⁵ l mol^–1 s^–1 at pH 2] and for the relative rates of attack of NH₃^+˙ on different substrates.