Interplay between hydrogen bond formation and multicenter pi-electron delocalization: intermolecular hydrogen bonds

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Molecular Interactions

Background:

• Hydrogen bonding is crucial in molecular interactions.
• Aromatic electron delocalization influences molecular properties.
• Understanding their interplay is key to predicting molecular behavior.

Purpose of the Study:

• To investigate the influence of aromatic electron delocalization on hydrogen bond strength.
• To quantify the relationship between delocalization and interaction energies.
• To validate findings using the quantum theory of atoms in molecules.

Main Methods:

• Multicenter delocalization analysis.
• Calculation of interaction energies between monomers at the B3LYP/6-311++G(d,p) level.
• Application of the quantum theory of atoms in molecules (QTAIM).

Main Results:

• Aromatic electron delocalization significantly affects hydrogen bond strength.
• Multicenter delocalization indices correlate perfectly with interaction energies.
• Observed effects align with predictions from resonance theory.

Conclusions:

• Electron delocalization is a critical factor in modulating hydrogen bond strength.
• QTAIM provides robust metrics for quantifying these interactions.
• The findings offer insights into molecular design for specific binding properties.