Self-assembly of cationic pyrene nanotubes

The controlled preparation of organic nanotubes via self-assembly of polycyclic aromatics is a contemporary challenge for supramolecular science. Here, we show that the self-assembly of pyrene-containing cationic amphiphiles, 3-(4-(pyren-6-yl)phenoxy)propan-1-ammonium salts (PyPA-Cl, PyPA-Br, and PyPA-SO4), can form high aspect ratio nanotubes with a uniform diameter distribution. We have also demonstrated that the counter anions also play an important role in the self-assembling results. The self-assembly of pyrene-containing cationic amphiphilic molecules with monovalent anions (Cl- and Br-) forms exclusively uniform nanotubes; whereas the self-assembly of amphiphiles with bivalent counter anions (SO42-) forms exclusively high aspect ratio nanoribbons. Furthermore, we have found that the diameter of the PyPA-Br nanotubes is larger than that of the PyPA-Cl nanotubes. The research results reported herein represent an important step towards the preparation of functional nanostructures with controlled 1D architectures.