Self-assembly of CuI dimers, featuring a bridging phosphole ligand, and ditopic cyano-substituted chromophores affords nanosize supramolecular cationic rectangles. Due to the short Cu-Cu distance in the bimetallic clips, the coordinated chromophores are forced to participate in cofacial pi-pi interactions as evidenced by X-ray data. In addition, intermolecular pi-pi interactions in the solid state are observed leading to infinite columns of pi-stacked (para-phenylenevinylene)-based chromophores.

The synthesis of phosphole-modified aza[6]helicenes and the complexation of these pi-conjugated ditopic ligands with metallic ions are described. The chiroptical properties of these metal-bis(helicene) assemblies were experimentally evaluated and studied by first-principles theoretical calculations. The results show that the metal impacts the chiroptical properties of these complexes through electronic interactions with the chiral pi-conjugated ligands.