Table 2 Acid dissociation constants determined for H4pypa-peg, H4edta and other structurally related APC ligands previously reported18,57.

From: Tuning aminopolycarboxylate chelators for efficient complexation of trivalent actinides

HnL

H4pypa-pega

H4edtaa

H4pypab

H4py4pac

HL3-

7.44 (1)

8.71 (1)

7.78 (1)

6.96 (1)

H2L2-

6.45 (1)

6.23 (1)

6.78 (1)

6.07 (1)

H3L-

3.92 (1)

2.48 (3)

3.69 (1)

4.06 (2)

H4L(aq)

3.37 (1)

2.08 (1)

3.02 (1)

3.58 (2)

H5L+

2.45 (2)

–

2.23 (2)

2.71 (3)

H6L2+

1.43 (4)

–

2.06 (6)

2.55 (4)

H7L3+

–

–

1.70 (2)

2.31 (4)

H8L4+

–

–

 − 0.37 (1)*

–

H9L5+

–

–

 − 0.58 (2)*

–

  1. aI = 2.0 M (Na+/H+)ClO4.
  2. bFrom Ref. 18; I = 0.16 M NaCl and uncertainties reported to 1σ.
  3. cFrom Ref. 57; I = 0.16 M NaCl and uncertainties reported to 1σ.
  4. *Measured using UV/Vis spectroscopy.
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