IBIMOL   23987
INSTITUTO DE BIOQUIMICA Y MEDICINA MOLECULAR PROFESOR ALBERTO BOVERIS
Unidad Ejecutora - UE
artículos
Título:
Conformational and electronic (AIM/NBO) study of unsubstituted A-type dimeric proanthocyanidin.
Autor/es:
ROSANA M. LOBAYAN; ALICIA H. JUBERT; MARTÍN G. VITALE; ALICIA B. POMILIO
Revista:
JOURNAL OF MOLECULAR MODELING - (Online)
Editorial:
Springer
Referencias:
Año: 2008 p. 1 - 14
ISSN:
0948-5023
Resumen:
The conformational space of the unsubstituted A-type dimeric proanthocyanidin was scanned using  molecular dynamics at a semiempirical level, and complemented with functional density calculations. The lowest energy conformers were obtained. Electronic distributions were analysed at a higher calculation level, thus improving the basis set. A topological study based on Baderfs theory (AIM: atoms in molecules) and natural bond orbital (NBO) framework was performed. Furthermore, molecular electrostatic potential maps (MEPs) were obtained and analysed. NMR chemical shifts were calculated at ab initio level and further compared with previous experimental values; coupling constants were also calculated. The stereochemistry of the molecule is thoroughly discussed, revealing the key role that hyperconjugative interactions play in defining experimental trends. These results show the versatility of geminal spin-spin coupling  2J(C-1Œ,O) as a probe for stereochemical studies of proanthocyanidins.   Keywords: Atoms in molecules . Dimeric procyanidin . Density functional theory . Nuclear magnetic resonance . Natural bond orbital analysis . Topological properties