- Vargas Jentzsch, A.; Emery, D.; Mareda, J.; Nayak, S. K.; Metrangolo, P.; Resnati, G.; Sakai, N.; Matile, S. “Transmembrane Anion Transport Mediated by Halogen-Bond Donors” Nat. Commun. 2012, 3, 905
In biology and chemistry, the transport of anions across lipid bilayer membranes is usually achieved by sophisticated supramolecular architectures. Significant size reduction of transporters is hampered by the intrinsically hydrophilic nature of typical anion binding functionalities, hydrogen-bond donors or cations. To maximize the atom efficiency of anion transport to the extreme, the hydrophobic nature, directionality, and strength of halogen bonds appeared most promising. Unlike the ubiquitous, structurally similar hydrogen bonds, halogen bonds have never really been explored for anion transport. Here, we report that transport across lipid bilayers can be achieved with small perfluorinated molecules that are equipped with strong halogen-bond donors. At extreme reductionism down to the “single-carbon” transporter, activity is observed with trifluoroiodomethane (boiling point = -22 ºC). Contrary to the destructive action of small-molecule detergents, transport with halogen bonds is leakage-free, cooperative, non-ohmic and highly selective (anion/cation permeability ratios as high as 37).