Helical organization in foldable aromatic oligoamides by a continuous hydrogen-bonding network

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Oligoaromatic foldamers are synthetic molecules with potential applications in materials science.
• Controlling the conformational flexibility of foldamers is crucial for designing predictable structures.
• Internal hydrogen-bonding networks offer a strategy for stabilizing specific conformations.

Purpose of the Study:

• To investigate the effect of a continuous internal hydrogen-bonding network on the conformational flexibility of oligoaromatic foldamers.
• To establish the helical ordering in these foldamers in solution and solid states.
• To corroborate experimental findings with computational molecular modeling.

Main Methods:

• Synthesis of oligoaromatic foldamers with a lengthened backbone.
• 2D NOESY spectroscopy to study molecular conformation in solution.
• X-ray diffraction to analyze crystal structure and solid-state conformation.
• Computational molecular modeling to support experimental data.

Main Results:

• Introduction of a continuous internal hydrogen-bonding network significantly suppressed conformational flexibility.
• Helical ordering was observed over extended segments (up to six aromatic repeating units).
• Experimental results were consistent with computational predictions, confirming helical propagation.

Conclusions:

• Continuous internal hydrogen-bonding networks are effective in controlling foldamer conformation.
• These networks promote stable helical structures in oligoaromatic foldamers.
• The findings provide insights into the design of ordered molecular strands for advanced applications.