Related Experiment Video
Updated: May 13, 2026

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
The anomeric effect on the basis of natural bond orbital analysis
1Department of Chemistry, Federal University of Lavras, Lavras, Brazil. matheus@dqi.ufla.br
Abstract:
The anomeric effect has been assigned as being due to hyperconjugation, electrostatic/steric interactions or exchange effects; thus, there is no general consensus about its actual origin. The classical hyperconjugation model, usually investigated using natural bond orbital (NBO) analysis, has been arbitrarily refuted because it would not explain some cases of the preferred equatorial anomer over the axial one in polar solution. In this study, hyperconjugation was shown to be dependent on the medium and NBO analysis explains quite well the estimated amounts of axial and equatorial 2-substituted tetrahydropyrans (substituents = F, OH, NH2 and CN) both in the gas phase and aqueous solution. Overall, there is no reason to abandon the hyperconjugation model as it plays a dominating role of the anomeric effect in some systems, while NBO analysis reproduces the energetic profiles on the basis of both hyperconjugative and Lewis-type contributions.
More Related Videos
08:04Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
06:35Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Related Concept Videos
Molecular Orbital Theory II
MO Theory and Covalent Bonding
Molecular Orbital Theory I
π Electron Effects on Chemical Shift: Overview
π Molecular Orbitals of the Allyl Cation and Anion
Valence Bond Theory and Hybridized Orbitals
A σ bond (single bond in a Lewis structure) is a covalent bond in which the electron density is...