Table 1.
Overall (log β) and stepwise (log K) thermodynamic protonation constants of L1′, L2 and L3 and their stability constants with Zr4+ in aqueous solution at 25.0 °C. Literature data for Me-AHA are provided for comparison.15
| Species | L1′ a | L2 b | L3 b | Me-AHA c | ||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| log β | log K | log β | log K | log β | log K | log β | log K | |
| LHd | 5.01 (7)e | 5.01 | 8.83 (4) | 8.83 | 9.55 (3) | 9.55 | 8.75 | 8.75 |
| LH2 | - | - | - | - | 12.54 (4) | 2.99 | - | - |
| ZrL3 | 31.3 (1)f | 31.3 | - | - | 41.1 (3) | 41.3 | 28.66 (5) | 3.44 |
| ZrL3H | 40.2 (1)f | 8.9 | 36.0 (6) | 36.0 (6) | 43.0 (4) | 2.4 | - | - |
| ZrL4 | 49.40 (1)f | 18.1 | 45.5 (1) | - | 49.27 (5) | 8.7 | 45.98 (1) | 17.32 |
| ZrL4(OH) | 41.97 (1)f | −7.43 | 35.9 (1) | −9.6 | - | - | - | - |
a
25.0 °C, I = 0.1 M in KCl;
b
25.0 °C, I = 0.2 M in KNO3;
c
I = 0.1 M KNO3, previously reported data, see Guérard et al. 18;
d
Charges are omitted for clarity.
e
Values in parentheses are standard deviations in the last significant digit;
f
Constants determined by UV spectrophotometric titration.