A Molecular orbital study of the rotation about the CC bond in styrene

  • Bock C
  • Trachtman M
  • George P
  • 4

    Readers

    Mendeley users who have this article in their library.
  • 54

    Citations

    Citations of this article.

Abstract

The geometry and energy of styrene have been calculated using the 6-31G basis set as a function of the CβC2C1C2dihedral angle-Φ = 0°(cis), 15°, 30°, 60° and 90° - assuming that the vinyl and phenyl groups remain planar, but otherwise with full geometry optimization. Similar calculations have been carried out for 1,3-butadiene and 3-methylene-1,4-pentadiene (MPD) where rotation about 180° generates a different and not the same conformer. The torsional potential energy curve for styrene has a very flat minimum Φ = 0, i.e. the cis structure is the most stable, whereas butadiene and MPD have minima in the region Φ = 37° to 40°, indicative of more stable gauche structures. For styrene the barrier height Φ = 90° is 131.1 KJ mol-1. These results provide strong support for the potential function obtained by Hollas and Ridley from single level vibronic fluorescence and other spectroscopic data. The distortion of the benzene ring brought about the vinyl group substitution is discussed, also the variation of the C/C and H/C bond lenghts with Φ and the change in charge on the vinyl group and the polarity of the various bonds in the conversion of the cis into the 90° gauche conformer. The stabilization energy for styrene relative to that for benzene has been evaluated according to various criteria, and, in addition, the energy associated with the distortion of the ring. © 1985.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Charles W. Bock

  • Mendel Trachtman

  • Philip George

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free