Pi-interaction

In chemistry, π-effects or π-interactions are a type of non-covalent interaction that involves π systems.

[1] Non-covalent interactions involving π systems are pivotal to biological events such as protein-ligand recognition.

[2] The most common types of π-interactions involve: [5] [6][7] Anion and π–aromatic systems (typically electron-deficient) create an interaction that is associated with the repulsive forces of the structures.

[11] In addition to this being depicted in the solid state, there is also evidence that the interaction is present in solution.

[12] π-effects have an important contribution to biological systems since they provide a significant amount of binding enthalpy.

Neurotransmitters produce most of their biological effect by binding to the active site of a protein receptor.

The trimethyl ammonium group of Ach binds to the aromatic residue of tryptophan (Trp).

The indole site provides a much more intense region of negative electrostatic potential than benzene and phenol residue of Phe and Tyr.

π systems are important building blocks in supramolecular assembly because of their versatile noncovalent interactions with various functional groups.