Preparation and Properties of a Soluble Polypyrrole−Polypyridyl−Ruthenium(II)−Viologen Dyad

• Published in: The journal of physical chemistry. B 2003-03, Vol.107 (12), p.2684-2692
• Main Authors: Martre, Agnès, Laguitton-Pasquier, Hélène, Deronzier, Alain, Harriman, Anthony
• Format: Article
• Language: English
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp021645j

Two different kinds of bisviologen-linked [Ru(bpy)3]2+ complexes bearing pyrrole groups were synthesized. We attempt to photopolymerize these dyad systems in the presence of an irreversible oxidative species (O2 or diazonium salts). The success of the photopolymerization appears to be strongly dependent on the design of the dyad, i.e., the relative arrangement among the [Ru(bpy)3]2+ chromophore, the viologen acceptor, and the polymerizable pyrrole groups. Electrochemical and photophysical characterization of the monomers and of the soluble photopolymer has been made. The intramolecular electron transfer from the 3MLCT excited state of the Ru chromophore to the viologen groups has been evidenced as well as the reverse process. We pay special attention to the photostability of the viologen moieties in the presence of O2. The photodegradation of the monoreduced viologen in the presence of O2 provides an emissive species at 546 nm. This photodegradation is not observed in the polymer system. Finally, it has been found that electroreductive precipitation of the photopolymer allows the coating of electrode surfaces with electroactive films exhibiting the redox features of the dyad.