| Texto completo | |
| Autor(es): |
Silva, Weslley G. D. P.
;
Braga, Carolyne B.
;
Rittner, Roberto
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Beilstein Journal of Organic Chemistry; v. 13, p. 925-937, MAY 17 2017. |
| Citações Web of Science: | 3 |
| Resumo | |
The understanding of the conformational behavior of amino acids and their derivatives is a challenging task. Here, the conformational analysis of esterified and N-acetylated derivatives of L-methionine and L-cysteine using a combination of H-1 NMR and electronic structure calculations is reported. The geometries and energies of the most stable conformers in isolated phase and taking into account the implicit solvent effects, according to the integral equation formalism polarizable continuum model (IEF-PCM), were obtained at the omega B97X-D/aug-cc-pVTZ level. The conformational preferences of the compounds in solution were also determined from experimental and theoretical 3J(HH) coupling constants analysis in different aprotic solvents. The results showed that the conformational stability of the esterified derivatives is not very sensitive to solvent effects, whereas the conformational equilibrium of the N-acetylated derivatives changes in the presence of solvent. According to the natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM) and noncovalent interactions (NCI) methodologies, the conformational preferences for the compounds are not dictated by intramolecular hydrogen bonding, but by a joint contribution of hyperconjugative and steric effects. (AU) | |
| Processo FAPESP: | 12/18567-4 - Investigação conformacional e das interações intramoleculares de derivados de aminoácidos utilizando as espectroscopias de RMN e IV e cálculos teóricos |
| Beneficiário: | Carolyne Brustolin Braga |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 14/25903-6 - Estudos de estrutura molecular de alguns aminoácidos e dipeptídios |
| Beneficiário: | Roberto Rittner Neto |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 16/12005-5 - Análise conformacional de derivados de aminoácidos: uma abordagem teórica e experimental |
| Beneficiário: | Weslley Guilherme Dias de Paiva Silva |
| Modalidade de apoio: | Bolsas no Brasil - Mestrado |