Table 3. Revised association constants for 1 from previously obtained data using receptors 2 and 3 as model systems.

Anions	Macroscopic association constants
	K 11 (M–1) a	K 11( Z / S ) (M–1) b , d	K 12 (M–1) c , d
Cl–	(2.30 ± 0.06) × 102	8.0 × 101	1.59 × 103
Br–	(1.50 ± 0.06) × 102	1.00 × 102	1.59 × 103
HSO4 –	(3.70 ± 0.06) × 102	2.00 × 102	1.00 × 104
OAc–	(2.11 ± 0.002) × 104	4.60 × 103	5.25 × 106

^aValues determined from re-fitting of titration data to a stepwise 1 : 2 host/guest model with the K ₁₂ value held constant.

^bValues calculated from expected statistically corrected equilibrium relationship (K _{( Z / S )} = 2K _m).

^cValues calculated from expected statistically corrected equilibrium relationship (K ₁₂ = αK _m ²) and assumed α = 1.

^dValues for K _m were assumed to be equal to the determined association constant for 3 with the corresponding anion.