Theoretical study of Z isomers of A-type dimeric proanthocyanidins substituted with R=H, OH and OCH3 : stability and reactivity properties

• Autores: Bentz, Erika Natalia; Jubert, Alicia Haydeé; Pomilio, Alicia Beatriz; Lobayan, Rosana María
• Año de publicación: 2010
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Journal of Molecular Modeling, 2010, vol. 16, no. 12, p. 1895-1909.
• Materia: Dimeric proanthocyanidins; Density functional theory; Atoms in molecules; NBO analysis; Topological properties; Maps of electrostatic potential
• Institución: Universidad Nacional del Nordeste

Fil: Bentz, Erika Natalia. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Bentz, Erika Natalia. Universidad de la Cuenca del Plata. Facultad de Ingeniería; Argentina.
Fil: Jubert, Alicia Haydeé. Universidad Nacional de La Plata. Facultad de Ciencias Exactas y Facultad de Ingeniería; Argentina.
Fil: Pomilio, Alicia Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Bioquímica y Medicina Molecular; Argentina.
Fil: Lobayan, Rosana María. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Lobayan, Rosana María. Universidad de la Cuenca del Plata. Facultad de Ingeniería; Argentina.
The stereochemistry of A-type dimeric proantho- cyanidins was studied, focusing on the factors that determine it, and the changes that occur with R = OCH3, R′ = H, and R = OH, R′ = H as substituents, starting with the study of the conformational space of each species. Using molecular dynamics at a semiempirical level, and complementing with functional density calculations, two conformers of lowest energy were characterized for R = H, eight conformers for R = OH, and three conformers for R = OCH3 . Electronic distributions were analyzed at a higher calculation level, thus improving the basis set. Intramolecular interactions were examined and characterized by the theory of atoms in molecules (AIM). Detailed natural bond orbitals (NBO) analysis allowed the description of subtle stereo- electronic aspects of fundamental importance for understand- ing the stabilization and antioxidant function of these structures. The study was enriched by a deep analysis of maps of molecular electrostatic potential (MEP). The coordinated analysis of MEP, together with the NBO and AIM results, allowed us to rationalize novel distribution aspects of the potential created in the space around a molecule.