The degree of lipophilicity of compounds 3-4 and 8-9 was quantified by calculating the octanol-water partition coefficients (clog P) using the online VCCLab ALOGPS2.1 applet, and the values are displayed in Table . The clog P values of para-SF5 derivatives 5 and 10 could not be accurately calculated using the online VCCLab applet; however, it is reported extensively in the literature that these groups are more lipophilic than para-CF3 compounds. Previous research by the our group and others has demonstrated that lipophilicity is a crucial parameter dictating the transport activity of synthetic mobile carriers. Systems that are too lipophilic cannot diffuse into the aqueous phase or pass through the barrier formed by the polar head groups, which is necessary to extract or release of an anion into the aqueous bulk. This can become the rate-limiting step of the transport process. The greater lipophilicity of bis-CF3 receptor 4 (clog P = 6.41) could potentially slow its transport rate compared to compound 3, which has a more moderate degree of lipophilicity (clog P = 3.96).