Hydrogen bonded aryl amide and hydrazide oligomers: a new generation of preorganized soft frameworks.

Hydrogen bonded aryl amide and hydrazide foldamers may adopt folded, zigzag or other extended conformations, depending on the positions of the amides and hydrogen bonding sites on the aromatic rings. In recent years, several series of such preorganized frameworks have been developed as efficient acyclic receptors for binding both neutral and ionic guests. The backbones can also be readily modified and appended with discrete functional units. Therefore, they have also been widely utilized in designing new molecular tweezers, for assembling ordered supramolecular architectures, and for directing the formation of complicated macrocyclic systems. This feature article highlights the recent advances, with a primary focus on our own work.