Tweezer-type binding cavity formed by the helical folding of a carbazole–pyridine oligomer

Abstract

We have synthesised a new aromatic foldamer based on the carbazole–pyridine oligomers that adopt helical conformations via dipole–dipole interactions and π-stacking between two ethynyl bond-linked monomers. This foldamer scaffold has been further modified into a synthetic receptor with a tweezer-type binding cavity outside the helical backbone upon folding, in contrast to most aromatic foldamers with internal binding cavities. The tweezer-type cavity is composed of two parallel pyrenyl planes, allowing for the intercalation of a naphthalenediimide guest via π-stacking and CH⋯O interactions, as demonstrated using its ¹H NMR spectra and X-ray crystal structure.