Anomeric effect associated with the electron delocalization,electrostaic model associated with the dipole-dipole interactionsand steric effect impacts on the configura onal proper es of ۲,۳-dihalo -۱,۴-dioxane. A hybrid density functional study and naturalbond orbital interpretation.

The heterocyclic compounds containing oxygen, phosphorus and selenium have maintained the interest ofresearchers [۱-۳]. In this work, the impacts of the anomeric effect associated with the electron delocalization,electrostatic model associated with the dipole-dipole interactions and steric hindrances on the configurationalproperties of ۲,۳-difleoro-۱,۴-dioxane( ۱), ۲,۳-dichloro-۱,۴-dioxane(۲) and ۲,۳-dibromo-۱,۴-dioxane( ۳) havebeen investigated using the hybrid-DFT based method (B۳LYP/۶-۳۱G*) and natural bond orbital(NBO)interpretations (Scheme ۱).Based on the calculated, the increase of the calculated Gibbs free energy differences between the equatorialaxialand axial-axial configurations [ i.e. (Geq-ax-Gax-ax )] from compound ۱ to compound ۳ can be justifiedby the increase of the AE=AE eq-ax -AE ax-ax the calculated total dipole moment value differences betweenequatorial-axial and axial-axial configurations [ i.e. ( eq-ax-ax-ax )] decrease from compounds ۱→۳. Thecalculated total dipole moment value [ i.e. ( eq-ax-ax-ax )] decrease from compounds ۱→۳. Consequently, therationalization of the conformational preference solely in terms of the electrostatic model associated with thedipole-dipole interactions fails to account for compounds ۱→۳.