Conformational aspects of malic acid: A multidisciplinary approach
| Autor: | Jan-Remt Mellema, Pieter F. W. Stouten, Jan Kroon, Bas R. Leeflang, Bouke P. van Eijck |
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| Rok vydání: | 1988 |
| Předmět: |
Coupling constant
Quantitative Biology::Biomolecules education.field_of_study Chemistry Organic Chemistry Population Crystal structure Analytical Chemistry Inorganic Chemistry Molecular dynamics chemistry.chemical_compound Computational chemistry Ionization Molecule Malic acid education Conformational isomerism Spectroscopy |
| Zdroj: | Journal of Molecular Structure. 189:65-80 |
| ISSN: | 0022-2860 |
| DOI: | 10.1016/0022-2860(88)80213-8 |
| Popis: | Malic acid molecules can adopt three different staggered conformations of minimum energy with respect to rotation around the central C-C bond: gauche - (g- ), trans (t) and gauche + (g+ ). The conformational behaviour of the acid and of its dissociated forms has been studied by means of NMR experiments and Molecular Dynamics simulations and the results are compared with a statistical analysis of crystal structures and with Molecular Mechanics calculations. Specific coupling constants for all three ionization states were determined. Coupling constants of the three staggered rotamers were calculated and by comparison with the specific coupling constants of each ionization state rotamer populations were determined. Observed and calculated populations are similar, although the gauche + population resulting from the NMR experiment is significantly higher than predicted by the other methods. All techniques indicate that gauche + is the minor conformer of the neutral molecule. It is also shown that water-acid interactions play a very important role in describing the conformational behaviour of malic acid properly. |
| Databáze: | OpenAIRE |
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