Nature of anion-templated pi(+)-pi(+) interactions

Abstract

Interaction between positively charged aromatic groups (pi(+)-pi(+)) is characterized by anti-parallel, displaced-stacked structures in the presence of counteranions. Binding energies of pyridinium, N-methylpyridinium and N-methylimidazolium dimers are much larger than that of benzene-pyridine (pi-pi) and pyridinium-benzene (pi(+)-pi). Stabilization is attributed to attractive electrostatic interaction with significant dispersion contribution.