Table 2. Association constants (M^–1) from NMR spectroscopic titrations at 298 K ^a .

Solvent	Toluene	Chloroform	Acetonitrile
Guest
Host
	31 ± 1	19 ± 2	<1
	40 ± 1	20 ± 1	<1
	62 ± 5	52 ± 2	<1
	1300 ± 50	850 ± 60	19 ± 1
	1 ± 1	<1	<1

^aErrors determined by 2 × standard deviation of multiple repeat titrations.