Table 5.

Transport flux for different guests mediated by 6 at neutral pH.

Guesta	Transport flux [μmolcm−2min−1]	Control [μmolcm−2 min−1]
FITC-choline 9	8.9 +0.2 × 10−6	0.00
FITC-adamantane 10	7.3 ± 0.2 × 10−7	4.36 × 10−7
NBD-choline 11	5.6 ± 0.2 × 10−5	9.61 × 10−6
Dansyl choline 12	4.6 ±0.1 × 10−5b	5.20 × 10−5b
carboxyfluoresceinc	1.6 ±0.1 × 10−5	1.54 × 10−5
NBD chloride	2.0 + 0.1 × 10−8	not measuredd

^a6 (500 μm) in CH₂Cl₂; guests (500 μm) in water, stirred for 144 h at 400 rpm. The aqueous phase was measured by UV/Vis spec-troscopy and compared to standard calibration curves after appropriate dilution. The results are reported as an average of duplicate runs with maximum deviation from the mean. See Exp. Sect. and Supporting Information for full details.

^bFor guest 12, the flux was less than the control experiment; we determined that 6 extracts and retains the difference in the organic layer.

^cCarboxyfluorescein was used at 250 μm due to solubility issues at higher concentrations.

^dThe transport rate with host 6 was so low that the control experiment was superfluous.