Selected best-fit parameters obtained from the analysis of the 1/T11H NMRD profiles (298 and 310 K) and 17O NMR data for Gd(HPADO3A), Gd(BzHPADO3A), and Gd(PipHPADO3A).
| Parametera | Gd(HPADO3A) | Gd(BzHPADO3A) | Gd(PipHPADO3A) | |||
|---|---|---|---|---|---|---|
| pH 4.2 | pH 7.4 | pH 4.2 | pH 7.4 | pH 4.2 | pH 7.4 | |
|
9.8 (2) | 4.3 (1) | 7.2 (1) | 4.5 (1) | 5.3 (2) | 4.6 (1) |
|
— | 6.7 (1) | — | 7.7 (1) | — | 8.5 (1) |
| r 1 pr 298 (mM−1 s−1) | 4.99 (2) | — | 2.87 (2) | — | 1.12 (3) | — |
| Δ 2 (1019 s−2) | 12.0 (7) | 8.5 (1.1) | 6.8 (1.6) | 10.2 (1.4) | 10.1 (1.0) | 3.5 (9) |
| τ 298 V (ps) | 4.5 (6) | 13.8 (8) | 5.0 (9) | 13.1 (9) | 10.4 (7) | 25.2 (9) |
| τ 298 M (ns) | 24.5 (5) | 20.2 (2.4) | 21.6b | 24.2 (2.1) | 21.6b | 45.0 (1.4) |
| τ 298 R (ps) | 62.0 (1.2) | 62.0 (1.3) | 70.8 (2.1) | 70.8 (1.5) | 82.2 (1.5) | 82.2 (2.0) |
| ΔHM (kJ mol−1) | 15.5 (7) | 14.9 (9) | — | 13.0 (5) | — | 7.5 (3) |
| A/h (106 rad s−1) | −3.4 (1) | −3.4 (1) | −3.4b | −3.4 (1) | −3.4b | −3.4 (1) |
| q SS | 5 | 5 | 4 | 4 | 3 | 3 |
| τ SS R (ps) | 30.0 (2.5) | 12.7 (9) | 24.5 (2.1) | 23.2 (1.0) | 24.0 (1.3) | 10.1 (9) |
a
The parameters fixed in the fitting procedure are q = 1, rGdO = 2.5 Å, rGdH = 3.0 Å, aGdH = 4.0 Å, 298DGdH = 2.25 × 10−5 cm2 s−1, ER = 18 kJ mol−1, Ev = 1 kJ mol−1, and rGdH(SS) = 3.5 Å.18
b
These values were fixed considering the value obtained for Gd(HPADO3A) at pH 4.2.