Cation-chloride cotransport mediated by an ion pair transporter.

Ion transport mediated by an ion pair receptor 1 bearing both cation and anion binding sites is presented. The ion pair binding property was revealed by means of 1H NMR titrations in organic solutions and X-ray analysis in the solid state. Single crystal structures demonstrated that 1 and CaI2 formed a solvent-separated ion-pair complex with two iodides each interacting with a triazine ring through anion-π interactions, whereas the calcium ion is bound by a pentaethylene glycol moiety. The ion transport activity was studied by monitoring the efflux of ions from salt-loaded EYPC large unilamellar vesicles (EYPC-LUVs) using ion selective electrodes. Chloride transport across the membrane mediated by the ion pair receptor through K+/Cl- or Na+/Cl- cotransport with a selectivity towards the K+/Cl- symport was realized.