Dealing with Hydrogen Bonding on the Conformational Preference of 1,3-Aminopropanols: Experimental and Molecular Dynamics Approaches

Autor(es)

Batista, Patrick R. ^[1] ; Karas, Lucas J. ^[2] ; Viesser, Renan V. ^[3] ; de Oliveira, Cynthia C. ^[4] ; Goncalves, Marcos B. ^[4] ; Tormena, Claudio F. ^[3] ; Rittner, Roberto ^[3] ; Ducati, Lucas C. ^[1] ; de Oliveira, Paulo R. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, Av Prof Lineu Prestes, POB 748, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 - USA

^[3] Univ Estadual Campinas, Inst Chem, Phys Organ Chem Lab, POB 6154, BR-13083970 Campinas, SP - Brazil

^[4] Fed Technol Univ Parana, Acad Dept Phys, BR-80230901 Curitiba, Parana - Brazil

^[5] Fed Technol Univ Parana, Dept Chem & Biol, Conformat Anal & Renewable Resources Lab, POB 5000, BR-81280340 Curitiba, Parana - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry A; v. 123, n. 40, p. 8583-8594, OCT 10 2019.
• Citações Web of Science: 0

Resumo

This study expands the knowledge on the conformational preference of 1,3-amino alcohols in the gas phase and in solution. By employing Fourier transform infrared spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, density functional theory (DFT) calculations, quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) analysis, and molecular dynamics (MD), the compounds 3-aminopropan-1-ol (1), 3-methylaminopropan-1-ol (2), and 3-dimethylaminopropan-1-ol (3) are evaluated. The results show that the most stable conformation of each compound in the gas phase and in nonpolar solvents exhibited an O-H center dot center dot center dot N intramolecular hydrogen bond (IHB). Based on the experimental and theoretical OH-stretching frequencies, the IHB becomes stronger from 1 to 3. In addition, from the experimental NMR J-couplings, the IHB conformers are predominant in nonbasic solvents, representing 70-80% of the conformational equilibrium, while in basic solvents, such conformers only represent 10%. DFT calculations and QTAIM analysis in the gas phase support the occurrence of IHBs in these compounds. The MD simulation indicates that the non-hydrogen-bonded conformers are the lowest energy conformations in the solution because of molecular interactions with the solvent, while they are absent in the implicit solvation model based on density. NBO analysis suggests that methyl groups attached on the nitrogen atom affect the charge transfer energy involved in the IHB. This effect occurs mostly because of a decrease in the s-character of the LPN orbital along with weakening of the charge transfer from LPN to sigma{*}OH, which is caused by an increase in the C-C-N bond angle. (AU)

• Processo FAPESP: 17/20890-1 - Avaliação dos mecanismos de blindagem e de transmissão dos acoplamentos em RMN de 1H, 13C e 19F
• Beneficiário: Renan Vidal Viesser
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/17750-3 - Efeito do Solvente em Parâmetros Espectroscópicos de RMN por Dinâmica Molecular ab initio
• Beneficiário: Lucas Colucci Ducati
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/08541-6 - Ressonância magnética nuclear: além da determinação estrutural
• Beneficiário: Claudio Francisco Tormena
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• 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: 18/07308-4 - Efeito do solvente em cálculos de tensor blindagem e constante de acoplamento de complexos dinucleares de platina (III) via dinâmica molecular ab initio
• Beneficiário: Patrick Rodrigues Batista
• Modalidade de apoio: Bolsas no Brasil - Doutorado