2.B.57. The Heavy Pnictogenium Cation (HPC) Family
Work on the complexation of fluoride anions using group 15 Lewis acids has led to the investigation of the use of these main group compounds as anion transporters. Park et al. 2019 reported on the anion transport properties of tetraarylstibonium and tetraarylbismuthonium cations of the general formula [Ph3PnAr]+ with Pn = Sb or Bi and with Ar = phenyl, naphthyl, anthryl, or pyrenyl. Using EYPC-based large unilamellar vesicles, they showed that these main group cations transport hydroxide, fluoride and chloride anions across phospholipid bilayers. A comparison of the properties of [Ph3SbAnt]+ and [Ph3BiAnt]+ (Ant = 9-anthryl) illustrated the favorable role played by the Lewis acidity of the central pnictogen element with respect to the anion transport. They found that [Ph3SbAnt]+ accelerates the fluoride-induced hemolysis of human red blood cells, an effect that was attributed to the transporter-facilitated influx of toxic fluoride anions (Park et al. 2019).