Explain why cyclooctatetraene is not aromatic? Strategy: Apply Huckel's rule and use the polygon-and-circle method for deriving the relative energies of the piMOs.

Explain why cyclooctatetraene is not aromatic? Strategy: Apply Huckel

1.	Explain why cyclooctatetraene is not aromatic? Strategy: Apply Huckel's rule and use the polygon-and-circle method for deriving the relative energies of the piMOs.
Answer» Solution : Cyclooctatetraence has total of eight `pi` electrons. Eight is not a Huckel number, i.e., not a `4N+2` number it is a `4n` number. Assuming cyclooctatetraene to be planar, we can apply the polygon-and-crcle METHOD. Like benzene, it does not have a closed shell of `pi` electrons. It has an unpaired ELECTRON in each of the TWO nonbonding orbitals.Molecules with unpaired electrons (radicals) are not usually stable, they are typically highly reactive and unstable. A planar form of cyclooctateraene is therefore not at all like benzene and Hence cannot be AROMATIC.