Large Aromatic Amide Helices via Living Polycondensation

Abstract

We employ a living polymerization strategy and a crescent-shaped monomer to synthesize large aromatic amide helices with cavity sizes exceeding 1 nm. These polymeric foldamer helices are stabilized by a continuous strand of three-center hydrogen bonds, ensuring structural integrity. Our method efficiently yields polymeric helices of varying lengths while also producing macrocycles as side products when targeting higher molecular weights. The isolation and characterization of a 7-mer macrocycle provided key insights into the number of repeat units required to complete a full turn of the corresponding polymeric helix. Additionally, macrocycles were obtained in greater quantities by performing the polycondensation in the absence of an initiator. This straightforward and versatile approach paves the way for the development of novel materials with potential applications in host-guest chemistry, catalysis, and molecular transport.