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Anion Transport with Pnictogen Bonds in Direct Comparison with Chalcogen and Halogen Bonds

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journal contribution
posted on 08.01.2019, 12:18 authored by Lucia M. Lee, Maria Tsemperouli, Amalia I. Poblador-Bahamonde, Sebastian Benz, Naomi Sakai, Kaori Sugihara, Stefan Matile
In this Communication, we introduce transmembrane anion transport with pnictogen-bonding compounds and compare their characteristics with chalcogen- and halogen-bonding analogues. Tellurium-centered chalcogen bonds are at least as active as antimony-centered pnictogen bonds, whereas iodine-centered halogen bonds are 3 orders of magnitude less active. Irregular voltage-dependent single-channel currents, high gating charges, and efficient dye leakage support for the formation of bulky, membrane-disruptive supramolecular amphiphiles due to “too strong” binding of anions to tris­(perfluorophenyl)­stibanes. In contrast, the chalcogen-bonding bis­(perfluorophenyl)­tellanes do not cause leakage and excel as carriers with nanomolar activity, with P(Cl/Na) = 10.4 for anion/cation selectivity and P(Cl/NO3) = 4.5 for anion selectivity. The selectivities are lower with pnictogen-bonding carriers because their membrane-disturbing 3D structure also affects weaker binders (P(Cl/Na) = 2.1, P(Cl/NO3) = 2.5). Their 2D structure, directionality, hydrophobicity, and support from proximal anion−π interactions are suggested to contribute to the unique power of chalcogen bonds to transport anions across lipid bilayer membranes.