A simple model system for the study of carbohydrate--aromatic interactions.

Area of Science:

• Carbohydrate Chemistry
• Supramolecular Chemistry
• Computational Chemistry

Background:

• Intramolecular interactions are crucial for molecular structure and function.
• Carbohydrate-arene interactions are increasingly recognized for their role in biological systems.
• Designing molecules with specific conformational properties is essential for various applications.

Purpose of the Study:

• To investigate the formation and nature of intramolecular interactions between monosaccharides and phenyl rings.
• To synthesize and analyze a series of molecules featuring different monosaccharides linked to an aromatic moiety.
• To understand how these interactions affect the overall 3D structure and energetics of the molecules.

Main Methods:

• Synthesis of novel molecular scaffolds incorporating four distinct monosaccharides (glucose, galactose, N-acetyl-glucosamine, N-acetyl-galactosamine) and a phenyl ring.
• Nuclear Magnetic Resonance (NMR) spectroscopy to evaluate sugar-aromatic distances and conformational dynamics.
• Molecular modeling and ab initio calculations (B3LYP/DZV(2d,p)) to analyze interaction energetics and electronic properties.

Main Results:

• A consistent and persistent intramolecular distance between the sugar and aromatic ring was observed across all synthesized molecules.
• The observed interaction was independent of the specific monosaccharide and the linker's conformational flexibility.
• Computational analysis revealed the electronic nature of the carbohydrate-arene interaction, confirming its stabilizing effect.
• Significant influence of these interactions on the overall molecular shape and energetics was demonstrated.

Conclusions:

• Intramolecular aromatic-sugar interactions can be readily established when sterically allowed.
• These interactions play a significant role in dictating molecular conformation and stability.
• The findings provide valuable insights for the rational design of structural mimics of complex oligosaccharides for therapeutic or material applications.