The hydrogen bonding association between 1-ferrocenylmethylthymine (T) and 9-octyladenine (A) in chloroform was studied by cyclic voltammetry and single potential step chronoamperometry. The model to analyse the equilibrium between the free T and the associated species (TA) was based on the limiting current measurements of the anodic oxidation of a ferrocene redox center included in the structure of T. The limiting current measurements ultimately depend on the difference of the diffusion coefficients that characterise the free and associated species in solution. The value of the equilibrium constant for the association process obtained by chronoamperometry was confirmed by simulation of the voltammetric behaviour considering a square reaction scheme of electron transfer and association processes. (C) 2004 Published by Elsevier B.V.