Directional Threading and Sliding of a Dissymmetrical Foldamer Helix on Dissymmetrical Axles.

Abstract

We have investigated the self-assembly of a dissymmetrical aromatic oligoamide helix on linear amido-carbamate rods. A dissymmetric sequence bearing two differentiated ends is able to wrap around dissymmetric dumbbell guest molecules. Structural and thermodynamic investigations allowed us to decipher the mode of binding of the helix that can bind specifically to the amide and carbamate groups of the rod. In parallel kinetic studies of threading and sliding of the helix along linear axles were also monitored by 1 H NMR. Results show that threading of a dissymmetrical host can be kinetically biased by the nature of the guest terminus allowing a preferential sense of sliding of the helix. The study presented below further demonstrates the valuable potential of foldaxanes to combine designed molecular recognition patterns with fine control of self-assembly kinetics to conceive complex supramolecular events.