Photoswitchable Bis(amidopyrroles): Modulating Anion Transport Activity Independent of Binding Affinity.

Toward photocontrol of anion transport across the bilayer membrane, stiff-stilbene, which has dimethyl substituents in the five-membered rings, is functionalized with amidopyrrole units. UV-vis and 1 H NMR studies show high photostability and photoconversion yields. Where the photoaddressable ( E )- and ( Z )-isomers exhibit comparable binding affinities, as determined by 1 H NMR titrations, fluorescence-based transport assays reveal significantly higher transport activity for the ( Z )-isomers. Changing the binding affinity is thus not a necessity for modulating transport. Additionally, transport can be triggered in situ by light.