Controllable Columnar Organization of Positively Charged Polycyclic Aromatic Hydrocarbons by Choice of Counterions

A novel columnar organization of ionic complexes based on 9-phenylbenzo[1,2]quinolizino[3,4,5,6-fed]phenanthridinylium (PQP) has been achieved via ionic self-assembly. These complexes represent the first family of polycyclic aromatic hydrocarbons containing a large charged aromatic core with controllable columnar organization in both the crystalline and liquid-crystalline phases. The single-crystal structure of the ionic complex with a benzenesulfonate anion exhibits a staggered dimer arrangement of PQP cations that further establishes columnar superstructures. The use of sulfonate anions with long alkyl tails leads to well-ordered discotic columnar mesophases with an identical staggered packing of the PQP cations.