On binding forces between aromatic ring and quaternary ammonium compound

Ab initio calculations for complexes of the tetramethylammonium cation (Me4N+) and the ammonium cation (H4N+) with benzene and water help examine the nature of binding forces of acetylcholine with its deactivating enzyme, acetylcholinesterase, and cation-pi interactions. Charge-quadrupole and charge-polarizability interactions are responsible for the binding forces of Me4N+ with benzene. Me4N+ exhibits stronger binding with benzene while H4N+ shows higher binding with water.