Electroactive [2]catenanes

[2]Catenanes are intriguing species composed of two interlocked macrocycles, whose unique structural and topological features can translate into new physico-chemical properties, including the ability to behave as molecular switches and mechanical machines. Electrochemical methods are an excellent choice for the characterization of catenanes incorporating redox-active units in their molecular components, and can also be employed to control the state of the system by electrochemically induced switching. Here we present a few examples of [2]catenanes which contain two identical or different electroactive units in each molecular ring and are characterized by intercomponent electron donor-acceptor interactions. These case studies show the potential of electrochemistry for providing fundamental information on the organization of the redox sites within the catenane structure, their electronic interactions, and the behaviour of the reduced/oxidized forms, particularly with regard to co-conformational changes induced by the electron-transfer processes.