Reversible photo-gated transmembrane channel assembled from an acylhydrazone-containing crown ether triad.

We have prepared a crown ether triad containing acylhydrazone units. In solution, the triad can self-assemble linearly to form an organogel. UV light-induced E/Z isomerization of the C[double bond, length as m-dash]N bond of the acylhydrazone unit endows the assembly with photo-sensitivity. The triad was able to insert into the lipid bilayer to form a supramolecular transmembrane channel which showed transport selectivity for NH4 + over K+ . The channel exhibited photo-gating properties under microscopic and macroscopic conditions. The transport of the channel could be reversibly switched off and on by irradiation with alternating 320 and 365 nm UV light as supported by the conductance measurements.