Supramolecular Ribbons from Amphiphilic Trisamides Self-Assembly

Abstract

Two amphiphilic C3-symmetric OPE-based trisamides have been synthesized and their self-assembling features investigated in solution and on surface. Variabletemperature UV vis experiments demonstrate the cooperative supramolecular polymerization of these trisamides that selfassemble by the operation of triple CdO 333 H N H-bonding arrays between the amide functional groups and π π stacking between the aromatic units. The helical organization of the aggregates has been demonstrated by circular dichroism at a concentration as low as 1 10 4 M in acetonitrile. In the reported trisamides, the large hydrophobic aromatic core acts as a solvophobic module impeding the interaction between the polar TEG chains and the amide H-bonds. This strategy makes unnecessary the separation of the amide functional groups to the polar tri(ethylene glycol) chains by paraffinic fragments. Achiral trisamide 1 self-assembles into flat ribbon-like structures that experience an amplification of chirality by the addition of a small amount of chiral 2 that generates twisted stripes