Arylene ethynylene macrocycles with intramolecular π-π stacking.

Arylene ethynylene macrocycles containing 9,10-anthrylene or 1,4-naphthylene units were synthesized. In chloroform, significant resonance upfield shifting was observed with β-protons of anthrylene and naphthylene in NMR spectra. This was considered to result from partial stacking of these aromatic units intramolecularly, driven by attractive π-π interactions. DFT calculations supported the proposed intramolecular stacking motif. Moreover, a liquid-crystal phase was exhibited by the anthrylene-containing macrocycle, by virtue of the unique discotic shape.