Planarization of 1,3,5,7-cyclooctatetraene as a result of a partial rehybridization at carbon atoms: an MP2/6-31G∗ and B3LYP/6-311G∗∗ study

Bending of the CCH bond angle maintaining D2d symmetry for COT leads to a partial rehybridization at carbon atoms which in consequence causes a significant decrease of bond length alternation and increase of planarization of the molecule. Analysis of the changes in exaltation of the magnetic susceptibility and NICS shows that the changes in π-electron structure are dramatic, much greater than that observed for a similar deformation of benzene.