Bidipyrrin Au III Complex as a Helical Charged π-Electronic System.

A series of ion pairs based on a bidipyrrin-Au III complex that acts as a stable helical π-electronic cation have been prepared via ion-pair metathesis. The helical cation, which exhibits NIR absorption and phosphorescence emission, formed solid-state ion-pairing assemblies, whose assembling modes depended on the properties of coexisting counteranions.