Preorganized Aryltriazole Foldamers as Effective Transmembrane Transporters for Chloride Anion

Preorganized aryltriazole foldamers <b>1</b> and <b>2</b> were designed and synthesized. NMR studies and X-ray analysis demonstrate that <b>1</b> adopts a crescent conformation driven by a series of continuous hydrogen bonds at the periphery of the foldamer, whereas <b>2</b> displays a coil conformation. NMR titrations reveal that the affinities of fully preorganized foldamer <b>1</b> for halogen anions are much stronger that those of partially preorganized foldamer <b>2</b>. Furthermore, it is found that such full preorganization makes <b>1</b> an effective transmembrane transporter for the chloride anion across a lipid bilayer

Chiral Selective Transmembrane Transport of Amino Acids through Artificial Channels

Peptide-appended pillar­[<i>n</i>]­arene (<i>n</i> = 5, 6) derivatives have been synthesized. ¹H NMR and IR studies revealed that the molecules adopt a tubular conformation in solution and lipid bilayer membranes. Kinetic measurements using the fluorescent labeling method with lipid vesicles revealed that these molecules can efficiently mediate the transport of amino acids across lipid membranes at a very low channel-to-lipid ratio (EC₅₀ = 0.002 mol %). In several cases, chiral selectivity for amino acid enantiomers was achieved, which is one of the key functions of natural amino acid channels