Multicomponent Photoactive Arrays Based on Novel Bistridentate Ruthenium Complexes

  • Rohan Kumar, Department of Photochemistry and Molecular Science, Uppsala University, Sweden
  • Mr Michael Jäger, Department of Photochemistry and Molecular Science, Uppsala University, Sweden
  • Ms Susanne Karlsson, Department of Photochemistry and Molecular Science, Uppsala University, Sweden
  • Professor Leif Hammarström, Department of Photochemistry and Molecular Science, Uppsala University, Sweden
  • Dr Olof Johansson, Department of Photochemistry and Molecular Science, Uppsala University, Sweden

    • The recent development in our laboratories of novel bistridentate ruthenium comlexes with excellent photophysical properties1 based on 2,6-di(quinolin-8-yl)pyridine (dqp),2 prompted the exploration of routes to donor-photosensitizer-acceptor arrays based on this motif. The rod-like character and lack of geometrical isomers, combined with the photophysical properties, gives an ideal system in which to investigate electron transfer phenomena, with the view to move to multiple electron, metal containing or photocatalytic systems.

    The synthetic strategies employed in the ligand synthesis for the donor and acceptor components of the system and an investigation of the co-ordination chemistry are discussed here (Figure 1). A variety of RuII and RuIII intermediates were investigated in order to allow co-ordination of reactive and redox active functional groups to the metal center. This has allowed the incorporation of a quinone unit, observed to act as an electron acceptor in the corresponding dyad. The preliminary photophysical investigation of this compound in organic and aqueous solutions as well as efforts toward the corresponding phenothiazine containing triad will be presented.

    1. Abrahamsson, M.; Jäger, M.; Österman, T.; Eriksson, L.; Persson, P.; Becker, H.-C.; Johansson, O.; Hammarström, L. A 3.0 micros Room Temperature Excited State Lifetime of a Bistridentate RuII-Polypyridine Complex for Rod-like Molecular Arrays. Journal of the American Chemical Society 2006, 128, 12616-12617.
    2. Jäger, M.; Eriksson, L.; Bergquist, J.; Johansson, O. Synthesis and Characterization of 2,6-Di(quinolin-8-yl)pyridines. New Ligands for Bistridentate RuII Complexes with Microsecond Luminescent Lifetimes. The Journal of Organic Chemistry 2007.