A theoretical exploration of unexpected amine⋯π interactions

Counterintuitive amine lone pair⋯π interactions are computationally revealed by MP2 and CCSD(T) methods, attractive lone pair⋯π interactions are observed when the lone pair of nitrogen points toward the π system. Symmetry adapted perturbation theory (SAPT) calculations and atoms in molecules (AIM) analyses were performed and the origin of the calculated attractive interaction between nitrogen lone pairs and π rings is discussed. Dispersion effects were revealed to play a crucial role in the attractive lone pair⋯π interaction.