Ion-Pairing Assemblies Comprising Pyrrole-Based π-Electronic Systems

π-Electronic systems responsive to metal ions and anions are very fascinating because they can form a variety of ion complexes as building subunits, providing supramolecular assemblies that exhibit attractive electronic and electrooptical properties.¹  In fact, anion complexes of the anion-responsive π-systems have been found to construct ion-pair-based assembled structures as crystals, supramolecular gels, and thermotropic liquid crystals by combination with cationic species.  Derived from favorable overlap of charged π-planes, ion-pair-based materials with the contribution of charge-segregated arrangements provided charge carrier mobilities, which are often larger than corresponding charge-by-charge-based materials, showing superior semi-conductive properties.  Highly ordered arrangement of charged species, not only the ion complexes but also charged π-systems, has been found to be a key factor to exhibit the enhanced performance as fascinating electronic materials.

1. A recent review: Maeda, H. Bull. Chem. Soc. Jpn. 2013, 86, 1359–1399.