Premium
Does antiaromaticity imply net destabilization?
Author(s) -
Murray Jane S.,
Seminario Jorge M.,
Politzer Peter
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560490503
Subject(s) - antiaromaticity , cyclobutadiene , isodesmic reaction , delocalized electron , chemistry , molecule , computational chemistry , chemical physics , cyclooctatetraene , ab initio , density functional theory , aromaticity , organic chemistry
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 π 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 π electrons of the CC 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 resist the apparent opportunity for extensive © delocalization, but that it does not intrinsically imply net destabilization. © 1994 John Wiley & Sons, Inc.