Steady-state voltammetric study of the reduction of decamethylferrocenium in dichloromethane at microelectrodes

The reduction of decamethylferrocenium hexafluorophosphate in a low permittivity solvent, dichloromethane, was studied by steady-state voltammetry at microelectrodes, using tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The limiting current was used to calculate the diffusion coefficient of the decamethyferrocenium cation and of its ion pair with the hexafluorophosphate anion at 298.15 K by employing a recent theory (OCSB [K.B. Oldham, T.J. Cardwell, J.H. Santos, A.M. Bond, J. Electroanal. Chem. 430 (1997) 25]) which takes into account the effect of ion association on the limiting currents. The OCSB theory describes accurately the contribution of migrational processes to the overall Faradaic current when variable quantities of supporting electrolyte are added to the solution.