Synthesis of Organic Super-Electron-Donors by Reaction of Nitrous Oxide with N‑Heterocyclic Olefins

The
reaction of nitrous oxide (N2O) with N-heterocyclic
olefins (NHOs) results in cleavage of the N–O bond and formation
of azo-bridged NHO dimers. The latter represent very electron-rich
compounds with a low ionization energy. Cyclic voltammetry studies
show that the dimers can be classified as new organic super-electron-donors,
with a reducing power similar to what is found for tetraazafulvalene
derivatives. Mild oxidants are able to convert the neutral dimers
into radical cations, which can be isolated. Further oxidation gives
stable dications.