Single-Molecular Artificial Transmembrane Water Channels

Hydrazide-appended pillar[5]­arene derivatives have been
synthesized.
X-ray crystal structure analysis and 1H NMR studies revealed
that the molecules adopt unique tubular conformations. Inserting the
molecules into the lipid membranes of vesicles leads to the transport
of water through the channels produced by single molecules, as supported
by dynamic light scattering and cryo-SEM experiments. The channels
exhibit the transport activity at a very low channel to lipid ratio
(0.027 mol %), and a water permeability of 8.6 × 10–10 cm s–1 is realized. In addition, like natural
water channel proteins, the artificial systems also block the transport
of protons.