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Crescent oligoamides: from acyclic "macrocycles" to folding nanotubes
1Department of Chemistry, State University of New York, Buffalo 14260, USA. bgong@chem.buffalo.edu
Chemistry (Weinheim an Der Bergstrasse, Germany)
|November 7, 2001
Summary
Rigidified oligoarylamides fold into defined shapes like crescents, macrocycles, or helices due to hydrogen bonds. These structures create large internal cavities, enabling new nanotube designs.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Oligoarylamides are polymers with repeating arylamide units.
- Intramolecular hydrogen bonds (H-bonds) can rigidify polymer backbones.
- Well-defined conformations are crucial for creating functional materials.
Purpose of the Study:
- To investigate the conformational behavior of oligoarylamides with rigidified backbones.
- To explore the formation of internal cavities within these folded structures.
- To assess the potential for constructing novel molecular architectures like nanotubes.
Main Methods:
- Synthesis of oligoarylamides with varying backbone lengths.
- Conformational analysis using techniques like NMR spectroscopy and X-ray crystallography.
- Solubility studies in different solvent polarities (nonpolar and polar).
Main Results:
- Oligoarylamides with intramolecular H-bonds adopt well-defined conformations (crescents, broken macrocycles, helices).
- Folded structures exhibit a large interior cavity (approx. 10 Å) in macrocyclic and helical forms.
- Conformations are independent of chain length and stable in various solvents.
Conclusions:
- Intramolecular H-bonding is an effective strategy for controlling oligoarylamide conformation.
- Folded oligoarylamides with internal cavities can be designed.
- This approach shows promise for creating novel acyclic macrocycles and nanotubes with tunable cavities.