Table 2 Protonation constants and stability constants of Ligand-T, Ligand-L and DOTA18.

From: Design and synthesis of chiral DOTA-based MRI contrast agents with remarkable relaxivities

log KiH

Ligand-Ta

Ligand-La

DOTAb

log K1H

11.30 (0.07)

13.53 (0.25)

11.14

log K2H

11.10 (0.09)

10.25 (0.12)

9.69

log K3H

10.30 (0.28)

9.90 (0.20)

4.85

log K4H

6.08 (0.30)

4.63 (0.19)

3.95

∑log KiH

38.78

38.31

29.62

log KGdL

30.01b

/

25.58(32)

  1. aI = 1.0 M NMe4Cl, at 25 °C.
  2. bI = 1.0 M KCl, at 25 °C, where KiH = [HiL]/[Hi-1L][H+], SD were shown in brackets.
  3. bI = 0.1 M NMe4Cl, at 25 °C31.
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