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| Author(s): |
Rodrigo Antonio Cormanich
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Química |
| Defense date: | 2011-07-15 |
| Examining board members: |
Roberto Rittner Neto;
João Pedro Farah;
Rogério Custodio
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| Advisor: | Roberto Rittner Neto |
| Abstract | |
The conformational analysis of glycine, L-alanine, sarcosine and N,N-dimetilglycine aminoacids and L-valine, L-phenylalanine and L-tyrosine methyl esters, using theoretical calculations and H NMR and infrared spectroscopies, are reported in the present dissertation. All calculations were carried out at the B3LYP/aug-cc-pVDZ level of theory and compared with experimental data obtained for the L-valine, L-phenylanaline and L-tyrosine, using the H NMR and infrared spectroscopies. The JHH values in various solvents provided important informations about the populational variation with the environment changing to these three molecular systems. Conformer relative populations, obtained in solvents of different dieletric constant values, were also measured by the infrared spectra C=O stretching band deconvolution. The experimental results obtained in each solvent are in good agreement in comparison to the obtained structures using the implicit solvent model IEFPCM (Integral Equation Formalism Polarized Continuum Model) theoretical calculations and, therefore, validate the last ones. Indeed, in divergence with literature data, this work suggests, within the framework of natural bond orbital (NBO) and the quantum theory of atoms in molecules (QTAIM) analysis, that these important compounds conformational preferences are ruled by steric and hyperconjugative effects and not as due to possible intramolecular hydrogen bonding formation (AU) | |
| FAPESP's process: | 09/02715-1 - NMR spectroscopy and theoretical calculations in the conformational analysis of some essential aminoacids and their N-acetylated derivatives |
| Grantee: | Rodrigo Antonio Cormanich |
| Support Opportunities: | Scholarships in Brazil - Master |