Illustrated Glossary of Organic Chemistry

Aromatic-aromatic interaction (aromatic stacking, pi stacking): A noncovalent attractive force between two aromatic rings. Alignment of positive electrostatic potential on one ring with negative electrostatic potential on another ring forms an offset stack, or in pure benzene, a T-shaped stack. Also called 'pi stacking' but this label is misleading because it implies that stacking might occur in any structure with pi electrons.

Offset stacking


Stacked base pairs cause aromatic-aromatic interactions in DNA.