Self-association of aromatic oligoamide foldamers into double helices in water.

Heteromeric oligoamide foldamers composed of 8-amino-2-quinolinecarboxylic acid and 7-amino-8-fluoro-2-quinolinecarboxylic acid bearing cationic water-solubilizing side chains were prepared using solid-phase synthesis (SPS). The sequences were designed to adopt a single- or a double-helical motif depending on the nature of the solvent, DMSO or water, respectively. Self-association was demonstrated by NMR and mass spectrometry. Dimerization in water was found to be much stronger than observed previously in organic solvents for analogous oligoamide sequences.