Novel, Methanol Stable, Aromatic Oligoamide Foldamers

Significance

Several novel aromatic oligoamides were synthesized using well-established DCC coupling chemistry. The oligomers with n = 1-4 were found to fold into helical structures both in solution, as observed by ¹H NMR, COSY, NOESY, UV-Vis and fluorescence spectroscopy, and in the solid state, as observed by X-ray crystallography. Both intramolecular hydrogen bonding and aromatic stacking interactions are believed to contribute to the secondary structure. Furthermore, comparison of the ¹H NMR spectra in methanol and chloroform revealed greater stability of the helical structure in the former solvent. It was speculated that intermolecular hydrogen bonding between methanol and the helical structures was the root of this enhanced stability.