1.D.99. The Rigid-Rod Scaffold Anion Channel (RR-AC) Family Rigid-rod scafolds with tetrafluoroiodobenzyl side chains catalyze the transmembrane transport of Cl^- (Vargas Jentzsch and Matile 2013). Halogen bonds are ideal for transporting anions across lipid bilayer membranes. Linear alignment of these compounds for anion hopping along transmembrane rigid-rod scaffolds gives excellent activities with a cooperativity coefficient of m = 3.37 (Vargas Jentzsch and Matile 2013). The 'hopping’' pathway for the anions resulted because they can bind reversibly using both anion–π interactions and also halogen bonds with the σ-holes of the iodine atoms (see Fig. 8 in Gale et al. 2017).
References:
Gale, P.A., J.T. Davis, and R. Quesada. (2017). Anion transport and supramolecular medicinal chemistry. Chem Soc Rev 46: 2497-2519.
Vargas Jentzsch, A. and S. Matile. (2013). Transmembrane halogen-bonding cascades. J. Am. Chem. Soc. 135: 5302-5303.