Photomodulation of Transmembrane Transport and Potential by Stiff-Stilbene Based Bis(thio)ureas.

Membrane transport proteins fulfill important regulatory functions in biology with a common trait being their ability to respond to stimuli in the environment. Various small-molecule receptors, capable of mediating transmembrane transport, have been successfully developed. However, to confer stimuli-responsiveness on them poses a fundamental challenge. Here we demonstrate photocontrol of transmembrane transport and electric potential using bis(thio)ureas derived from stiff-stilbene. UV-vis and 1 H NMR spectroscopy are used to monitor E - Z photoisomerization of these bis(thio)ureas and 1 H NMR titrations reveal stronger binding of chloride to the ( Z )-form than to the ( E )-form. Additional insight into the binding properties is provided by single crystal X-ray crystallographic analysis and DFT geometry optimization. Importantly, the ( Z )-isomers are much more active in transmembrane transport than the respective ( E )-isomers as shown through various assays. As a result, both membrane transport and depolarization can be modulated upon irradiation, opening up new prospects toward light-based therapeutics as well as physiological and optopharmacological tools for studying anion transport-associated diseases and to stimulate neuronal activity, respectively.