Intermolecular interactions in molecular crystals: what's in a name?

Area of Science:

• Crystal engineering
• Solid-state chemistry
• Supramolecular chemistry

Background:

• Structure-property relationships are fundamental to crystal engineering.
• Non-canonical interactions (halogen, chalcogen, pnicogen, tetrel bonds) are increasingly recognized.
• Understanding intermolecular forces is key to designing materials with specific properties.

Purpose of the Study:

• To demonstrate a unified understanding of various intermolecular interactions.
• To link electron density redistribution to molecular electrostatic potential and interaction energies.
• To connect intermolecular interactions to macroscopic crystal properties.

Main Methods:

• Analysis of electron density redistribution during chemical bonding.
• Calculation and visualization of molecular electrostatic potential.
• Quantitative calculation and visualization of intermolecular interaction energies (electrostatic and dispersion components).

Main Results:

• All analyzed intermolecular interactions (including hydrogen bonds, halogen, chalcogen, pnicogen, and tetrel bonds) share a common origin in electron density redistribution.
• Molecular electrostatic potential directly correlates with these interactions.
• Visualization of interaction energy components provides insights into crystal architecture.

Conclusions:

• A unified theoretical framework simplifies the understanding of diverse intermolecular interactions in molecular crystals.
• This understanding facilitates the rational design of crystalline solids with targeted properties.
• The approach links fundamental electronic effects to observable crystal properties.