Cyclic voltammetry experiments were performed with a computer-controlled Autolab PGSTAT30 potentiostat in a three-electrode single-compartment cell (5 mL). The platinum working electrode consisted of a platinum wire sealed in a soft glass tube with a surface of A = 0.785 mm 2 , which was polished down to 0.25 μm with Buehler polishing paste prior to use to guarantee reproducible surfaces. The counter electrode consisted of a platinum wire and the reference electrode was an Ag/AgCl reference electrode. All potentials were internally referenced to the ferrocene/ferricenium couple (Fc/Fc + ). For the measurements, concentrations of 10 -3 M of the electroactive species were used in freshly distilled and deaerated dichloromethane (Lichrosolv, Merck) purified with a solvent purification equipment MB-SPS-800 from MBraun. Tetrabutylammonium hexafluorophosphate (Sigma-Aldrich, recrystallized twice from ethanol) was applied as the supporting electrolyte in a concentration of 0.1 M and the solution was blanketed with argon during the measurements.