Reversing selectivity of bambusuril macrocycles toward inorganic anions by installing spacious substituents on their portals.

Two chiral bambusurils, which are diastereomers to each other, show remarkable differences in their binding affinity and selectivity toward inorganic anions as determined by isothermal titration calorimetry. These differences are explained by quantum-chemical calculations.

Merging Bambus[6]uril and Biotin[6]uril into an Enantiomerically Pure Monofunctionalized Hybrid Macrocycle.

Bambus[6]urils and biotin[6]urils are macrocycles with an exceptional affinity for inorganic anions. Here, we investigated statistical condensation of 2,4-dibenzylglycoluril and d-biotin, monomers of the corresponding macrocycles, to prepare the enantiomerically pure macrocycle containing a single d-biotin and five glycoluril units. Host-guest properties of in chloroform solution and solid state were investigated.

Tuning CH Hydrogen Bond-Based Receptors toward Picomolar Anion Affinity via the Inductive Effect of Distant Substituents.

Inspired by nature, artificial hydrogen bond-based anion receptors have been developed to achieve high anion selectivity; however, their binding affinity is usually low. The potency of these receptors is usually increased by the introduction of aryl substituents, which withdraw electrons from their binding site through the resonance effect. Here, we show that the polarization of the C(sp )-H binding site of bambusuril receptors, and thus their potency to bind anions, can be modulated by the inductive effect.

Synthesis of Enantiomerically Pure Bambus[6]urils Utilizing Orthogonal Protection of Glycolurils.

A general strategy for the synthesis of 2,4'-disubstituted glycoluril enantiomers on a multigram scale using orthogonal protection is reported. The use of these glycolurils is demonstrated in the synthesis of enantiomerically pure bambus[6]uril macrocycles. Moreover, the deprotection of ()-1-phenylethyl substituents on the macrocycle was achieved, opening access to various chiral bambus[6]urils post-macrocyclization modification strategy.

Transmembrane transport of fluoride studied by time-resolved emission spectroscopy.

Here we present a new method to monitor fluoride transmembrane transport into liposomes using a europium(III) complex. We take advantage of the long emission lifetime of this probe to measure the transport activity of a fluorescent transporter. The high sensitivity, selectivity, and versatility of the assay allowed us to study different types of fluoride transporters and unravel their mechanisms of action.