Table 6.

Transport flux for 9 and 11, mediated by calixarenes 4 and 5, as a function of pH.

Hosta	Guest	Receiving phase	Transport flux [μmolcm−2min−1]	Control [μmolcm−2 min−1]
4	9	MQ water	1.6 × 10−5	0
	9	0.1 m HCl	1.2 × 10−5b	0
	11	MQ water	3.9 × 10−5	1.3 × 10−5
	11	0.1 m HCl	9.4 × 10−5	1.3 × 10−5
5	9	MQ water	0	0
	9	0.1 m HCl	1.9 × 10−6b	0
	11	MQ water	3.1 × 10−6	1.3 × 10−5
	11	0.1 m HCl	2.6 × 10−4	1.3 × 10–5

^aCalixarene-based receptors (500 μm) in CH₂Cl₂; guests were dissolved in water, stirred for 96 h at 400 rpm. The receiving phase was measured using a UV/Vis calibration curve after dilution.

^bA separate calibration curve was used for the acidified receiving phase due to changes in the absorbance of 9.