Table 1.

Acid dissociation constants (pK_a) of ligands (20% (v/v) ethanol-water mixed, 25.0 ± 0.1°C, I = 0.1 mol/L by NaCl) (log₁₀⁡β is cumulative acid dissociation constants).

Ligand	Species	log10⁡β	pKa Values
2a	LH3	11.37 ± 0.02	3.22 ± 0.01
	LH2	20.03 ± 0.03	8.66 ± 0.02
	LH	23.25 ± 0.03	11.37 ± 0.01
2b	LH3	11.16 ± 0.04	3.24 ± 0.01
	LH2	19.29 ± 0.05	8.13 ± 0.01
	LH	22.53 ± 0.05	11.16 ± 0.03
2c	LH3	11.08 ± 0.02	3.21 ± 0.02
	LH2	19.23 ± 0.03	8.15 ± 0.01
	LH	22.44 ± 0.03	11.08 ± 0.02
2d	LH3	10.95 ± 0.08	3.74 ± 0.04
	LH2	19.24 ± 0.09	8.29 ± 0.03
	LH	22.98 ± 0.09	10.95 ± 0.05
2e	LH3	11.12 ± 0.04	3.40 ± 0.02
	LH2	19.67 ± 0.04	8.55 ± 0.02
	LH	23.07 ± 0.05	11.12 ± 0.04
2f	LH3	10.87 ± 0.05	3.50 ± 0.03
	LH2	19.40 ± 0.07	8.53 ± 0.03
	LH	22.90 ± 0.08	10.87 ± 0.01
2g	LH4	12.70 ± 0.11	2.48 ± 0.07
	LH3	20.88 ± 0.13	3.80 ± 0.05
	LH2	24.68 ± 0.10	8.18 ± 0.06
	LH	27.16 ± 0.09	12.70 ± 0.05