Attractive acceptor-acceptor interactions in self-complementary quadruple hydrogen bonds for molecular self-assembly

Area of Science:

• Supramolecular Chemistry
• Chemical Physics

Background:

• Molecular self-assembly enables the creation of complex supramolecular structures beyond standard chemical synthesis.
• Understanding the driving forces of self-assembly is crucial for harnessing its potential.
• Self-complementary hydrogen bonding, utilizing donor (D) and acceptor (A) groups, is a key strategy.

Purpose of the Study:

• To investigate the driving forces behind molecular self-assembly, specifically focusing on hydrogen bonding patterns.
• To re-evaluate the traditional model of secondary interactions in self-complementary hydrogen bonding.
• To determine the nature of interactions between identical groups (D-D, A-A) in DDAA and DADA motifs.

Main Methods:

• High-end quantum chemical analysis was employed to study molecular interactions.
• Computational modeling was used to analyze the stability of different hydrogen bonding patterns.
• The study focused on DDAA/AADD and DADA/ADAD self-complementary motifs.

Main Results:

• Contrary to traditional assumptions, secondary acceptor-acceptor (A⋯A) interactions were found to be attractive.
• The DDAA hydrogen bonding pattern, often considered more stable, was re-examined in light of these findings.
• The study challenges the notion that all secondary interactions between identical groups are repulsive.

Conclusions:

• The traditional model explaining the stability of DDAA and DADA motifs based on repulsive secondary interactions is revised.
• Secondary A⋯A interactions are attractive, not repulsive, influencing the overall stability of supramolecular assemblies.
• This revised understanding of secondary interactions is critical for designing and predicting self-assembling molecular systems.