Bismuthenium Cations for the Transport of Chloride Anions via Pnictogen Bonding

Our interest in the design of heavy pnictogen-based Lewis acids for anion trafficking across biological membrane mimics has led us to investigate trivalent bismuthenium cations as chloride anion transporters. Here, we describe two chlorodiarylbismuthines, elaborated on a peri-substituted naphthalene backbone and stabilized by an adjacent thio- or seleno-ether functionality that engages the bismuth center in a Ch→Bi interaction (Ch=chalcogen). These new derivatives are stable in aqueous environment and readiliy transport chloride anions across the membrane of phospholipid-based vesicles loaded with KCl. In addition to establishing the use of such motifs in anion transport, this investigation shows that the Lewis acidity, lipophilicity, and thus chloride transport properties depend on the nature of the chalcogen.