Tris-carboxyamide and tris-sulfonamide-based anion receptors with cyanuric acid core are developed for transmembrane chloride transport.

A series of triazole–cyanostilbene receptors were designed and synthesized. The receptor binds with the anions through various CH···anion hydrogen bonding interactions, where strong binding was observed for SO4 2– anions followed by Cl–, Br–, NO3 –, and I–, calculated from the 1H NMR titration experiment. The NOESY NMR experiment of the receptor confirmed the formation of anion-induced folded conformation. The CH···anion hydrogen bonding interaction-mediated anion recognition and foldamer formation were further confirmed from geometry optimization studies of the anion-bound complex. The receptor transports Cl– anions efficiently compared to SO4 2– anions across the lipid bilayer membrane via a mobile carrier mechanism.

Photoswitchable acylhydrazone-based synthetic anionophores are reported. Single-crystal X-ray structure and 1 H NMR titration studies confirmed the chloride binding in solid and solution states. The ion transport activity of 1a was greatly attenuated through a phototriggered E to Z photoisomerization process, and the photoisomerized deactivated state showed high kinetic stability due to an intramolecular hydrogen bond. Switchable "OFF−ON" transport activity was achieved by the application of light and acid-catalyzed reactivation process.

Achieving superfast water transport by synthetically designed molecular artifacts, which exclude salts and protons, is a challenging task in separation science today, as it requires the concomitant presence of a...