The Rotational Barrier in Ethane: A Molecular Orbital Study

Molecules

Ramiro F. Quijano-Quiñones¹  Mariana Quesadas-Rojas¹  Gabriel Cuevas² 

[1] Laboratory of Pharmaceutical Chemistry, Faculty of Chemistry, Autonomous University of Yucatan, 41 No. 421 Col. Industrial, C.P. 97150, Merida, Yucatan, Mexico;Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510 Mexico D.F., Mexico;

关键词: staggered conformation;    ethane;    rotational barrier;    molecular orbital;    DFT;   

DOI  :  10.3390/molecules17044661

来源: mdpi

【 摘 要 】

The energy change on each Occupied Molecular Orbital as a function of rotation about the C-C bond in ethane was studied using the B3LYP, mPWB95 functional and MP2 methods with different basis sets. Also, the effect of the ZPE on rotational barrier was analyzed. We have found that σ and π energies contribution stabilize a staggered conformation. The σ_s molecular orbital stabilizes the staggered conformation while the stabilizes the eclipsed conformation and destabilize the staggered conformation. The π_z and molecular orbitals stabilize both the eclipsed and staggered conformations, which are destabilized by the π_v and molecular orbitals. The results show that the method of calculation has the effect of changing the behavior of the energy change in each Occupied Molecular Orbital energy as a function of the angle of rotation about the C–C bond in ethane. Finally, we found that if the molecular orbital energy contribution is deleted from the rotational energy, an inversion in conformational preference occurs.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.