Protonation equilibria and complex formation ability of 2-amino-3-aminomethyl-4,6-disubstituted pyridines
| Autor: | Z. Cimerman, Z. Štefanac |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Ligand
Inorganic chemistry Potentiometric titration Protonation Carbon-13 NMR Mass spectrometry Medicinal chemistry Inorganic Chemistry Metal chemistry.chemical_compound chemistry Stability constants of complexes visual_art Materials Chemistry visual_art.visual_art_medium Physical and Theoretical Chemistry Derivative (chemistry) |
| Zdroj: | Polyhedron. 4:259-268 |
| ISSN: | 0277-5387 |
| DOI: | 10.1016/s0277-5387(00)84498-8 |
| Popis: | The protonation equilibria of 2-amino-3-aminomethyl-4,6-disubstituted pyridines were studied by potentiometric titrations and by UV and 13C NMR spectrometry. Protonation constants log K1 and log K2 potentiometrically determined for 4-methoxymethyl-6-methyl (8.959 and 5.778), 6-methoxymethyl-4-methyl (8.964 and 5.407), and 4,6-dimethyl derivative (9.141 and 6.604), were compared with the values obtained by the spectrometric methods. Complex formation of these compounds with Cu(II), Ni(II), Zn(II) and Co(II) was investigated in solution whereby the outstanding effect of the pH value was established and the presence of the species with 1 : 1 and 2 : 1 ligand to metal ratios confirmed. Stability constants obtained by potentiometric titrations show a decrease of the complex stability in the order Cu > Ni > Zn with respective log β1 values of 5.85, 3.56 and 2.93. Series of complexes isolated in the crude state were characterized by elemental analyses and spectrometric data, the latter serving also as the basis for making an attempt at the discernment of the coordination mode and sites. |
| Databáze: | OpenAIRE |
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