AN AB INITIO AND DFT STUDIES OF THE CONFORMATIONAL STABILITY IN BRANCHED ALKANES: 3,4-AND 2,5-DIMETHYLHEXANES

 

S. Mouatarif, A. Aboulmouhajir*

?quipe de Recherche de Spectroscopie et Chimie Quantique, Laboratoire de Chimie Physique

Département de Chimie, Faculté des Sciences, Université Chouaib Doukkali, B. P. 20,24000 El Jadida, Maroc.

* Corresponding author. E-mail:  aboulmouhajir@yahoo.fr

Received: 15 December 2006; revised version accepted: 30 May 2007

 

Abstract

                The conformational analysis of 3,4- and 2,5-dimethylhexane (3,4-DMH and 2,5-DMH) was carried out. The geometry and the relative conformational energy were investigated at various levels of ab-initio theory : Hartree-Fock (HF) theory, M?ller-Plesset (MP) theory and density functional theory (DFT). A various basis sets were also tested. In addition, possible rotational barriers from the most stable conformer to the lowest secondary conformers and their correspondent inversion barriers were obtained at both HF/6-31G* and MP2/6-31G* methods.

 

Keywords: Ab-initio; DFT; Branched alkanes; Conformational enthalpy; Rotational barriers.

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