. Author manuscript; available in PMC: 2009 Dec 22.

Published in final edited form as: J Biol Inorg Chem. 2008 Dec 13;14(3):421–438. doi: 10.1007/s00775-008-0459-3

Table 1.

The protonation constants (log K_i) of selected DOTA-tetraamide ligands and the thermodynamic stability constants (log K_ML) of their complexes with endogenous divalent metal ions (M²⁺) (I = 1.0 M KCl, 25°C).

	DOTAM^a	DTMA^a	L^1a	L^2b	L⁴	L⁸	DOTA^c
Protonation constants
log K₁^H	9.08	9.56	9.33	9.19	8.69 ± 0.01	8.43 ± 0.01	12.60
log K₂^H	6.20	5.95	6.39	6.25	6.57 ± 0.01	6.94 ± 0.01	9.70
log K₃^H	-	-	-	4.08	-	-	4.50
log K₄^H	-	-	-	3.45	-	-	4.14
log K₅^H	-	-	-	3.20	-	-	2.32
log K₆^H	-	-	-	1.40	-	-	-
Stability constants
log K_MgL	4.65	4.33	4.49	4.34	4.47 ± 0.01	4.86 ± 0.01	11.15
log K_CaL	10.32	10.11	10.74	10.39	9.89 ± 0.01	10.34 ± 0.01	16.37
log K_CuL	14.50	14.61	16.40	13.39	14.83 ± 0.02	14.68 ± 0.03	22.72
log K_ZnL	13.77	13.66	16.55	-	15.00 ± 0.02	14.35 ± 0.02	18.17

^a)

from reference [5],

^b)

from reference [18],

^c)

from references [14–16].