Potential Functions of Internal Rotation around the Csp 2 -X Bonds and Intermolecular Interactions in the Compounds CH 2 = CHXCH 3 (X = O, S, Se)

Abstract

The potential functions of internal rotation around the Csp 2-X bonds in the CH2 = CHXCH3 molecules (X = O, S, Se) were determined by MP2/6-31G* and MP2/6-31G** calculations. The stationary points were identified by solution of vibrational problems. The rotation barriers were evaluated taking into account the zero-point vibration energy. The intramolecular interactions were considered in terms of the method of natural bond orbitals. The degrees of hybridization, energies, and populations of the orbitals of the lone electron pairs of the O, S, and Se atoms, the energies of their donor-acceptor interaction with the antibonding σ* and π* orbitals of the double bond, and the natural atomic charges in various conformations were determined.