Reactivity of Diarylnitrenium Ions

Abstract

Hydride abstraction from diarylamines with the trityl ion is explored in an attempt to generate a stable diarylnitrenium ion, Ar₂ N⁺ . Sequential H-atom abstraction reactions ensue. The first H-atom abstraction leads to intensely colored aminium radical cations, Ar₂ NH^.+ , some of which are quite stable. However, most undergo a second H-atom abstraction leading to ammonium ions, Ar₂ NH₂ ⁺ . In the absence of a ready source of H-atoms, a unique self-abstraction reaction occurs when Ar=Me₅ C₆ , leading to a novel iminium radical cation, Ar=N^.+ Ar, which decays via a second self H-atom abstraction reaction to give a stable iminium ion, Ar=N⁺ HAr. These products differ substantially from those derived via photochemically produced diarylnitrenium ions.

Keywords: aminium radical cation; bulky substituents; iminium radical cations; nitrenium ion; triplet.