HYPERCONJUGATION EFFECT ON THE STRUCTURAL STABILITY OF A TERT-BUTYL AND ITS DERIVED C4Hn(n = 4–10) ISOMERS

Abstract

The hyperconjugation effect on molecular structural stability is studied by performing first-principles calculations on the tert-butyl and its derived C 4 H n(n = 4–10) isomer structures. Four of the isomer structures with n = 7–10 were found to show hyperconjugation similar to that in the tert-butyl, with hyperconjugation orbital energies decreasing with the increase of the number of hydrogen atoms participating in the hyperconjugation (PIH). The distribution of charge carried by the PIH hydrogen atoms is uniform, which reveals a delocalization character in the electronic structures; and the PIH hydrogen atoms are found responsible for the main IR spectrum peak relating to C-H stretching vibration.