Fluoride anion complexation and transport using a stibonium cation stabilized by an intramolecular PO → Sb pnictogen bond.

We describe the synthesis of [o-Ph2P(O)(C6H4)SbPh3]+ ([2]+), an intramolecularly base-stabilized stibonium Lewis acid which was obtained by reaction of [o-Ph2P(C6H4)SbPh3]+ with NOBF4. This cation reacts with fluoride anions to afford the corresponding fluorostiborane o-Ph2P(O)(C6H4)SbFPh3, the structure of which indicates a strengthening of the PO → Sb interaction. When deployed in fluoride-containing POPC unilamellar vesicles, [2]+ behaves as a potent fluoride anion transporter whose activity greatly exceeds that of [Ph4Sb]+.