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

Toward photocontrolof anion transport across the bilayermembrane,stiff-stilbene, which has dimethyl substituents in the five-memberedrings, is functionalized with amidopyrrole units. UV-vis and H-1 NMR studies show high photostability and photoconversionyields. Where the photoaddressable (E)- and (Z)-isomers exhibit comparable binding affinities, as determinedby H-1 NMR titrations, fluorescence-based transport assaysreveal significantly higher transport activity for the (Z)-isomers. Changing the binding affinity is thus not a necessityfor modulating transport. Additionally, transport can be triggered in situ by light.