title: Chemically and electrochemically triggered assembly of viologen radicals: towards multiaddressable molecular switches.
abstract: We have established that bipyridinium radicals can be reversibly π-dimerized under the combined effects of chemical (proton transfer) and electrochemical (electron transfer) stimuli. Our investigations also led to the discovery that a bis-pyridinyl appended calixarene intermediate is involved in a fully reversible redox-triggered σ-dimerization process. The structure of the most stable intramolecular σ-dimer was provided by computational chemistry and its complete conversion into a noncovalent π-dimer could be triggered chemically by addition of protons, leading to the formation of protonated cation radicals. Theoretical data collected with the N-methylated and N-protonated π-dimers also support the existence of multivariant orientations in π-bonded dimers of viologen cation-radicals.
authors.affiliation: Laboratoire de Chimie (UMR5182), Université de Lyon 1, École Normale Supérieure de Lyon/CNRS, Lyon (France).
authors.forename: Christophe
authors.initials: C
authors.lastname: Kahlfuss
authors.forename: Estelle
authors.initials: E
authors.lastname: Métay
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Duclos
authors.forename: Marc
authors.initials: M
authors.lastname: Lemaire
authors.forename: Anne
authors.initials: A
authors.lastname: Milet
authors.forename: Eric
authors.initials: E
authors.lastname: Saint-Aman
authors.forename: Christophe
authors.initials: C
authors.lastname: Bucher
keywords: dimerization; electrochemistry; molecular devices; pi interactions; radical ions