Table 3. Logarithms of the Stability Constants for Cu(II) Complexes of L2, L2-Me, L2-Me3, L1,30L1-Me,30 and L1-Me3,30 Obtained by Potentiometric Measurements in 0.15 M NaClO4 at 298.1 ± 0.1 K.
| reactiona | L2 | L2-Me | L2-Me3 |
|---|---|---|---|
| Cu(II) + L ⇄ [CuL]2+ | 13.87(1)b | 16.13(5) | 16.4(1) |
| Cu(II) + H–1L– ⇄ [Cu(H–1L)]+ | 19.35(3) | 23.84(4) | 23.32(6) |
| [Cu(H–1L)]+ + H2O ⇄ [Cu(H–1L)(OH)] + H+ | –9.42(5) | –7.91(3) | –8.46(5) |
| L1 | L1-Me | L1-Me3 | |
|---|---|---|---|
| Cu(II) + L ⇄ [CuL]2+ | 17.78(2) | 18.5(1) | 16.44(3) |
| [CuL]2+ + H2O ⇄ [CuL(OH)]+ + H+ | –8.68(8) | –8.73(5) | –8.53(4) |
| [CuL(OH)]+ + H2O ⇄ [CuL(OH)2] + H+ | –10.7(1) | –10.7(2) | –11.31(8) |
a
H–1L corresponds to the ligands with deprotonated pyridinol moiety.
b
Values in parentheses are standard deviations in the last significant figure.