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

Cyclic voltammetry was pet-formed 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 [Cu-3(1)(2)](3+)-type complex. In addition, cyclic voltammetry performed at different temperatures and dynamic H-1 NMR indicate that the double strand complexes of 1 dissociate at a temperature higher than 90 degrees 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 [Cu-3(1)(2)](3+) takes about 10 min at 75 degrees C. The room-temperature electrochemical characteristics of [Cu-3(1)(2)](3+) are compared to those of the copper helicate of 5,5'-bis[(6-methyl-2,2'-bipyridyl-6'-yl) methyl]-2,2'-bipyridine (2) which was studied by cyclic voltammetry and by differential pulse voltammetry. (C) 1997 Elsevier Science S.A.