SELF-ASSEMBLING ORGANIC NANOTUBES BASED ON A CYCLIC PEPTIDE ARCHITECTURE

HOLLOW tubular structures of molecular dimensions may offer a variety of applications in chemistry, biochemistry and materials science. Concentric carbon nanotubes1,2 have attracted a great deal of attention, while the three-dimensional tubular pore structures of molecular sieves have long been exploited industrially3-8. Nanoscale tubes based on organic materials have also been reported previously9-13. Here we report the design, synthesis and characterization of a new class of organic nanotubes based on rationally designed cyclic polypeptides. When protonated, these compounds crystallize into tubular structures hundreds of nanometres long, with internal diameters of 7-8 angstrom. Support for the proposed tubular structures is provided by electron microscopy, electron diffraction, Fourier-transform infrared spectroscopy and molecular modelling. These tubes are open-ended, with uniform shape and internal diameter. We anticipate that they may have possible applications in inclusion chemistry, catalysis, molecular electronics and molecular separation technology.