Electrochemical characterization of a self-assembled double strand copper complex composed of three Cu⁺ and two ligands containing bis( bipyridine) bithiophene

Cyclic voltammetry was performed on the self-assembled double strand copper complex of 5,5′-bis [(6-methyl-2,2′-bipyridyl-6′-yl)methoxymethyl]-2,2′- bithiophene (1) at ambient temperature. The cyclic voltammetry of the copper complex of 1 is consistent with the formation of a [Cu₃(1)₂]³⁺-type complex. In addition, cyclic voltammetry performed at different temperatures and dynamic ¹H NMR indicate that the double strand complexes of 1 dissociate at a temperature higher than 90°C. However, this dissociation is reversible and cooling the sample regenerates the original cyclic voltammogram. Using fast switching of temperature we could demonstrate that reassemblage of the double strand complex [Cu₃(1)₂]³⁺ takes about 10min at 75°C. The room-temperature electrochemical characteristics of [Cu₃(1)₂]³⁺ are compared to those of the copper helicate of 5,5′-bis[(6-methyl-2,2′-bipyridyl-6′-yl)methoxy methyl]-2,2′-bipyridine (2) which was studied by cyclic voltammetry and by differential pulse voltammetry.