Competition between n → π* interactions and H-bonding: a way to stabilize aminoxyl anions and to improve electron transfer kinetics

A new approach to stabilization of the reduced state of nitroxides in solution is suggested. Thermodynamic stabilization of the strongly basic aminoxyl anions toward protonation and hydrogen bond formation with the solvent was achieved by intramolecular n → π* interactions. A new stable nitroxide radical bearing ortho-acyl group was synthesized to demonstrate this effect by means of cyclic voltammetry.