A Redox-Active Tetrathiafulvalene [2]Pseudorotaxane:  Spectroelectrochemical and Cyclic Voltammetric Studies of the Highly-Reversible Complexation/Decomplexation Process

The complexation of TTF 2 and cyclobis(paraquat- p -phenylene) 1 4+ has been studied by cyclic voltammetry and by spectroelectrochemistry: shifts in the redox potentials for the TTF and the 1 4+ components of 45 and 30 mV, respectively, occur upon complexation. Decomplexation of 2·1 4+ upon oxidation of the TTF unit to the cation radical species has been monitored by spectroelectrochemistry. The complexation/decomplexation process is highly reversible over at least 10 electrochemical cycles, and this process is accompanied by a color change of the solution from dark green (complexed) to pale brown (uncomplexed) which is clearly visible to the naked eye.