The electrochemical activity of 10%Fc12-PF6 was studied ex-situ by CV to test the stability over repeated redox cycling, and to investigate the diffusivity of the redox probe. The voltammograms collected at 0.1V s -1 are shown in Figure . In contrast to 10%Fc12-Br (Figure ), the 10%Fc12-PF6 system maintains most of its peak current and cyclic voltammogram shape characteristic of reversible electron transfer up to 200 cycles; the 70% activity loss observed in 10%Fc12-Br is here absent , thus confirming the hypothesis of Br -reactivity.