Does Antiaromaticity Imply Destabilization
Abstract
An analysis is presented of the results of earlier ab initio computational studies of cyclobutadiene, cyclooctatetraene and 1,4- dihydropyrazine. The first and third of these are normally categorized as antiaromatic. All three molecules are polyenes, even when the last two are forced into planar conformations. There is no driving. force for extensive pi delocalization, even when it would appear to have been facilitated. Calculated isodesmic energies show a net destabilization only in the case of cyclobutadiene, which we attribute to strain and repulsion between the pi electrons. of the C=C double bonds. The other two molecules have negative isodesmic energies indicative of net stabilizing effects. We conclude that the concept of antiaromaticity is useful for identifying molecules that resis the apparent opportunity for extensive pi delocalization, but that it does not intrinsically imply net destabilization.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 27, 1993
- Accession Number
- ADA274622
Entities
People
- Jane S. Murray
- Jorge M. Seminario
- Peter Politzer
Organizations
- University of New Orleans