Probing intramolecular interactions using molecular electrostatic potentials: changing electron density contours to...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Molecular Interactions

Background:

• Intramolecular interactions are crucial for molecular structure and properties.
• Traditional methods for identifying interactions, such as bond critical points, have limitations.
• Electrostatic potential on electron density surfaces offers a promising avenue for analysis.

Purpose of the Study:

• To develop and apply a novel method for characterizing intramolecular interactions.
• To investigate the nature (attractive or repulsive) of various intramolecular interactions.
• To demonstrate the utility of electrostatic potential on tailored electron density contours.

Main Methods:

• Optimizing molecular structures with intramolecular interactions.
• Identifying the 'nearly-touching contour' of electron density.
• Plotting electrostatic potential on these contours to determine interaction type.

Main Results:

• Electrostatic potential on close electron density contours effectively distinguishes attractive and repulsive intramolecular interactions.
• 1,5- and 1,6-interactions in phenols are attractive.
• Interactions in diethyl disulfides, biphenyl, and phenanthrene are repulsive.
• Bond critical points are neither necessary nor sufficient for identifying attractive interactions.

Conclusions:

• The proposed method provides a robust way to analyze intramolecular interactions.
• This approach clarifies the nature of interactions where bond critical points are absent or misleading.
• The findings advance the understanding of non-covalent interactions in diverse molecular systems.