This work introduces a new approach to transmembrane anion transport based on lipophilic and Lewis acidic tetraarylstibonium and tetraarylbismuthonium cations. The stibonium cations are particularly appealing given that they readily transport hydroxide, fluoride, and chloride anions in synthetic vesicles. When combined with human erythrocytes, the most active stibonium cation uncovered in this study quickly localizes in the cell membranes and induces hemolysis when fluoride is present. This effect is assigned to the transporter-facilitated influx of toxic fluoride anions.

We describe a sulfonium/stibonium dication that behaves as a preanionophore activatable by glutathione (GSH). Indeed, this dication is reduced by GSH to yield a thioether/stibonium monocation that readily transports Cl− across phospholipid membranes.

Our long-standing interest in atypical bonding situations has recently led us to target complexes in which a metallobasic gold­(I) center is hydrogen-bonded to a nearby OH functionality. Here, we report on the synthesis and characterization of two neutral gold­(I) indazol-3-ylidene complexes bearing a carbinol or silanol group at the 4-position. As indicated by X-ray diffraction, 1H NMR spectroscopy, IR spectroscopy, and extensive computational modeling, the OH group of these derivatives is engaged in a bona fide Au···H–O interaction. In addition to shedding light on an elusive bonding situation, these results also indicate that increasing the acidity of the OH functionality is not necessarily beneficial to the stability of the Au­(I)···H–O interaction.

With the view of developing selective transmembrane anion transporters, a series of phosphonium boranes of general formula [p‐RPh2P(C6H4)BMes2]+ have been synthesized and evaluated. The results demonstrate that variation of the R group appended to the phosphorus atom informs the lipophilicity of these compounds, their Lewis acidity, as well as their transport activity. Anion transport experiments in POPC‐based large unilamellar vesicles show that these main‐group cations are highly selective for the fluoride anion, which is transported more than 20 times faster than the chloride anion. Finally, this work shows that the anion transport properties of these compounds are extremely sensitive to the steric crowding about the boron atom, pointing to the crucial involvement of the Group 13 element as the anion binding site.

A newly synthesized stibonium cation stabilized by an intramolecular PO → Sb pnictogen bond readily transports fluoride anions across phospholipid bilayers.