Monodirectional Photocycle Drives Proton Translocation

Journal of the American Chemical Society, vol. 145, pp. 21020–21026

Abstract

High Resolution Image Download MS PowerPoint Slide Photoisomerization of retinal is pivotal to ion translocation across the bacterial membrane and has served as an inspiration for the development of artificial molecular switches and machines. Light-driven synthetic systems in which a macrocyclic component transits along a nonsymmetric axle in a specific direction have been reported; however, unidirectional and repetitive translocation of protons has not been achieved. Herein, we describe a unique protonation-controlled isomerization behavior for hemi-indigo dyes bearing N-heterocycles, featuring intramolecular hydrogen bonds. Light-induced isomerization from the Z to E isomer is unlocked when protonated, while reverse E → Z photoisomerization occurs in the neutral state. As a consequence, associated protons are displaced in a preferred direction with respect to the photoswitchable scaffold. These results will prove to be critical in developing artificial systems in which concentration gradients can be effectively generated using (solar) light energy.

Authors 4

1. Nol Duindam Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands

2. Michelle van Dongen Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands

3. Maxime A. Siegler

   Johns Hopkins University

   Affiliation as printed

   Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States

4. Sander J. Wezenberg corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands