Triply Branched Viologen Stars: Synthesis and Polymerization by Peripheral Benzyl Coupling (Eur. J. Org. Chem. 5/2012)

Abstract

The cover picture shows the synthesis of new star-shaped oligoviologens (left to right), consisting of a trifold central branching unit and three linear branches (up to 5.8 nm long) of alternating benzyl (blue) and phenyl viologens (red). Up to 24 electrons can be injected into the viologen subunits at four well-separated electrode potentials (green vertical region). The corresponding localized spin densities in a single short branch are shown in the grey region. Viologen stars with peripheral benzylic bromides are reductively cross-linked to yield a polymer with persisting star subunits (brown region). The star-shaped multielectron molecules are supposed to have potential applications as electron sponges, as switchable organic magnets, as nanometer-sized components in composite nanomaterials, and so on. Details are discussed in the article by L. Walder et. al. on p. 913 ff.