Triarylamine molecules appended with crown-ethers or carboxylic moieties form self-assembled supramolecular channels within lipid bilayers. Fluorescence assays and voltage clamp studies reveal that the self-assemblies incorporating the crown ethers work as single channels for the selective transport of K or Rb. The X-ray crystallographic structures confirm the mutual columnar self-assembly of triarylamines and crown-ethers. The dimensional fit of K cations within the 18-crown-6 leads to a partial dehydration and to the formation of alternating K cation-water wires within the channel. This original type of organization may be regarded as a biomimetic alternative of columnar K-water wires observed for the natural KcsA channel. Supramolecular columnar arrangement was also shown for the triarylamine-carboxylic acid conjugate. In this latter case, stopped-flow light scattering analysis reveals the transport of water across lipid bilayer membranes with a relative water permeability as high as 17 μm s.
We describe a study of the equilibrium binding of Zn 2+ to binary mixtures of tridentate terpy-type ligands 1-3, which leads to the formation of a dynamic mixture of homo (4-6) and hetero (7-9) coordination compounds. We report the crystal structures of five such complexes (4, 5, 7-9) which assemble into complementary duplex compounds that further self-organize into double helical-or lamellar-type architectures in the solid state. The ligand exchange between homoduplex complexes in solution leads to the preferential formation of the heteroduplex complexes. As might be expected, these processes display a statistical distribution of homoduplex:heteroduplex:homoduplex complexes of 1:2:1 for the mixtures resulting from 4:6 and 5:6 ligands. However, complex 8 is preferred in a 4:5 mixture which presents a com-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.