. 2016 Sep 27;6:34024. doi: 10.1038/srep34024

Table 1. Protonation constants log K_i^H of L^1–3H₆ and other related compounds.

	Ligand
	L¹H₆^a	L²H₆^a	L³H₆^a	L⁴H₆^b	L⁵H₆^c	L⁶H₆^d
log K₁^H	12.9^e	12.9^e	12.9^e	12.9^e	12.9^e	12.9^e
log K₂^H	12.1^e	12.1^e	12.1^e	12.1^e	12.1^e	12.1^e
log K₃^H	11.3^e	11.3^e	11.3^e	11.26	11.3^e	11.3^e
log K₄^H	8.98 (5)	8.91 (6)	8.86 (8)	8.75	8.55	9.26
log K₅^H	7.56 (8)	7.52 (4)	7.43 (2)	8.61	7.5	8.65
log K₆^H	6.16 (7)	6.13 (5)	6.0 (5)	6.71	6.0	7.86
log K₇^H	—	—	—	5.88	—	—
Average^f	7.57	7.52	7.43	7.49	7.36	8.59

^aDetermined by spectrophotometric titration: [L^1–3H₆] = 2 × 10⁻⁵M; μ = 0.10 M KCl; T = 298.2 K; pH range = 6.5–10.0; 5.0 vol % methanol aqueous solution.

^bRef. ³⁰, μ = 0.10 M KNO₃.

^cRef. ³¹, 5.0 vol % methanol aqueous solution.

^dRef. ³², μ = 0.10 M KNO₃.

^eEstimated values.

^fAverage K_i^H of the three more acidic catecholamide protonation constants: ∑(log K₄^H + log K₅^H + log K₆^H)/3.

Table 1. Protonation constants log KiH of L1–3H6 and other related compounds.

Table 1. Protonation constants log K_i^H of L^1–3H₆ and other related compounds.