On the non-classical contribution in lone-pair-π interaction: IQA perspective.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Chemical Physics

Background:

• Lone-pair-π interactions are crucial in molecular recognition and self-assembly.
• Understanding these interactions requires detailed analysis of electronic and energetic contributions.

Purpose of the Study:

• To investigate the nature of lone-pair-π interactions between water and substituted π-rings.
• To differentiate the roles of electrostatic and exchange-correlation factors in complex formation.
• To elucidate the contribution of non-classical factors to the stabilization of water-π complexes.

Main Methods:

• Employed quantum chemical topology approaches, specifically the Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA).
• Analyzed interaction energies, electrostatic contributions, exchange-correlation effects, and deformation energies.

Main Results:

• Identified three classes of water-π complexes based on the interplay of electrostatic and exchange-correlation factors.
• Exchange-correlation interactions were found to be the dominant contributor to binding energy.
• Deformation energy significantly counterbalances the stabilizing exchange-correlation contribution.

Conclusions:

• Non-classical factors play a significant role in stabilizing lone-pair-π complexes.
• Despite the importance of quantum effects, simple electrostatic models can effectively describe water-π interactions due to energy counterbalancing.