The presence of the -OMe group in BU 5 resulted in a slight decrease in activity in comparison to 2, as concluded from the obtained transport curves (orange and green curves in Figure ) and fitted transport rate constants (Table ) and confirmed from an experiment at a 10-fold lower concentration (Figure , Table ). The polar -OMe group could interact with lipid headgroups or be hydrated at the membrane interface, inducing a penalty to the transport process by BU 5 as compared to 2. A decrease in transport activity for compounds containing ether groups was already observed for decalin-based transporters. 10 BUs 6-8 exhibited similar anion transport rates (red, green and blue curves in Figure ), with 6 transporting slightly faster than 7 and 8 (Table ). It can be deduced from the results that the variation of the -CF3 group to either -SCF3 or -OCF3 does not induce a significant change in the overall anion transport ability. This result corresponds to the similar activities found for BUs 1 and 2, which bear two -CF3 or -SCF3 groups per benzyl substituent. The lipophilicity of BUs 6 and 8 is predicted to be similar, with 7 being slightly more lipophilic, while the differences in the Ka values for chloride between these three BUs are also within one order of magnitude.