Table 3.
Protonation constants of thioglycolic acid, thiomalic acid, meso-2,3-dimercaptosuccinic acid (DMSA), dimercaptopropane sulfonate (DMPS), penicillamine, lipoic acid, dihydrolipoic acid, and some other simple ligands useful to characterize the acid behavior of SH ligands.
| Structure | Name | Acronym | Formula | MW | log K1 | log K2 | log K3 | log K4 |
|---|---|---|---|---|---|---|---|---|
|
Thioglycolic acid | TGA | C2H4O2S | 92.11 | [174] 9.96 | 3.44 | ||
|
Thiomalic acid | TMA | C4H6O4S | 150.15 | [174] 10.24 | 4.52 | 3.12 | |
|
2,3 Dimercapto propan-1-ol | BAL | C3H8OS2 | 124.23 | 10.8 | 8.7 | ||
|
meso-Dimercapto succinic acid | DMSA | C4H6O4S2 | 182.22 | [174] 12.05 | 9.65 | 3.43 | 2.71 |
|
Methyl-DMSA | MDMSA | C5H8O4S2 | 196.22 | [174] 9.98 | 7.15 | 2.8 | |
|
Dimethyl-DMSA | DDMSA | C6H10O4S2 | 210.22 | [174] 7.31 | 5.23 | ||
|
Unitiol | DMPS | C3H8O3S3 | 188.289 | [175] 11.38 | 8.69 | ||
|
d-Penicillamine | DPEN | C5H11NO2S | 149.212 | [176] 10.35 | 7.91 | 2.19 | |
|
Lipoic acid | LA | C8H14O2S2 | 206.343 | [177] 6.37 * $ 4.704(1) |
|||
|
Dihydrolipoic acid | DHLA | C8H16O2S2 | 208.343 | [178] 11.02 | 9.86 | 4.73 |
The protonation constants related to the SH groups are marked in red. * Determined in non-aqueous solvent, $ determined in this work.