. Author manuscript; available in PMC: 2009 Oct 2.

Published in final edited form as: Eur J Inorg Chem. 2007 Jul 31;2007(27):4340–4349. doi: 10.1002/ejic.200700354

Table 1.

Protonation constants of several DOTA-(amide)₄ ligands (I = 1.0 M KCl, T = 25 °C, values given in parentheses are standard deviations).

	DOTAM	DOTA-(MeAm)₄	DOTA-(EtAm)₄	DOTA-(gly-OEt)₄	DOTA-(gly)₄^a	DOTA^b
log K₁^H	9.08(1)	9.56(1)	9.33(2)	9.18(3)	9.19	12.60
	7.70^c	9.27^d
log K₂^H	6.44(1)	5.95(1)	6.39(3)	5.47(4)	6.25	9.70
	6.21^c	5.55^d
log K₃^H	–	1.56^d	–	1.82(6)	4.08	4.50
log K₄^H	–	–	–	–	3.45	4.14
log K₅^H	–	–	–	–	3.20	2.32
log K₆^H	–	–	–	–	1.40	–
Σlog K_i ^H	15.52	15.51	15.72	16.47	27.57	33.26

Ref.[11]

Ref.[20]

Ref.[12]

Refs.[14,15]