At the applied potential for electrografting (-0.4 V vs. Ag/AgNO₃ 0.01 M), the dC12TEMPO molecules, initially in their oxidized oxoammonium form (TEMPO⁺), are reduced to their radical form near the electrode surface (E₁/₂ TEMPO⁺/TEMPO = +0.40 V vs. Ag/AgNO₃ 0.01 M). Therefore, in the solution containing dC12TEMPONOBF4, all TEMPO derivatives near the working electrode exist in their radical form. In contrast, in the solution containing dC12TEMPOtBuONO/BF3, non-radical TEMPO-X species coexist with TEMPO radicals.