Hetero-dimeric covalent-organic pillars with aliphatic linkers
Abstract
Penta-bridged covalent bis-pillar[5]arenes have garnered significant attention recently as single-molecule nanotubular structures. In this study, we synthesized hetero-dimeric covalent-organic pillars (hetero-COPs) by coupling penta-aldehyde and penta-amine pillar[5]arene derivatives. NMR spectroscopic, mass spectrometric, and X-ray crystallographic analyses confirmed the formation of a pair of directionally asymmetrical hetero-COPs with an overall length of 1.8 nm. Furthermore, we observed social chiral sorting during the [1 + 1] imine condensation process of these macrocyclic building blocks. Although the synthetic efficiency requires further improvement, our findings provide valuable insights into the design of directional nanotubes based on bis-pillar[5]arene.