Diels–Alder/Retro-Diels–Alder Reactions as Fold Altering Chemical Stimuli to Control the Self-Assembly of Aromatic Oligoamides

Self-assembly of aromatic oligoamides into multihelical structures is a powerful strategy for developing complex and functional molecular architectures. As the hybridization process is directed by the folded state of the oligomers, inducing changes in the folding can be used to control the self-assembly. As one approach for this, Diels-Alder reactions on diazaanthracene monomers allow site-specific modification of aromatic oligoamides. The reaction leads to a bend in the monomer that, in turn, distorts the structure of the oligomer. Herein, we show that this strategy can be used to control the self-assembly of the oligomers. Using reversible Diels-Alder reactions allows switching between distinct folded states with different self-assembly preferences. This strategy can be applied during oligomer synthesis to prevent self-assembly or postsynthetically to disassemble multihelical structures. In complex systems containing multiple oligomers, we show that the modification can further be used to direct social versus narcissistic self-sorting, allowing for the switch between homomeric and heteromeric double helical assemblies.