Nanotubes With A Twist

Novel noncovalent helical nanotubular structures have been discovered by Jeremy K. M. Sanders and coworkers at the University of Cambridge, England (Angew. Chem. Int. Ed., DOI: 10.1002/anie.200603348). The organic nanotubes (shown) are constructed of amino acid naphthalenediimide derivatives that assemble by hydrogen bonding in nonpolar solvents or in the solid state. The Cambridge team prepared the molecular building blocks in one high-yielding step from mixtures of commercially available 1,4,5,8-naphthalenetetracarboxylic dianhydride and amino acids, using microwave dielectric heating. The supramolecular nanotubes have a right-handed or left-handed helical structure, depending on the chirality of the constituent amino acids. "The self-assembly process is simple, effectively instantaneous, reversible and dynamic, and largely independent of the amino acid side chain," Sanders notes. "These new helical nanotubes are materials with exciting potential for host-guest interactions."