antiaromatic

[‚an·tē‚ar·ə′mad·ik]

(chemistry)

A cyclic compound with delocalized electrons that does not obey Hückel's rule, and is much less stable than similar nonaromatic compounds.

References in periodicals archive ?

Aromatic systems have pretty negative NICS values, antiaromatic systems have strongly positive NICS values, and nonaromatic cyclic systems should have NICS values close to zero [35,42-44].

Theoretical Study on the Photoelectric Properties of a Class of Copolymers Based on Benzodithiophene for Solar Cells

When the value of the HOMA index is less than zero, the structure is antiaromatic.

Does the Intramolecular Hydrogen Bond Affect the Spectroscopic Properties of Bicyclic Diazole Heterocycles?

Therefore, according to Huckels Rule, they should be antiaromatic [1].

Study of the Molecular Properties of Mono- and Binuclear Metal s-Indacenyl Complexes with Ir, Rh, and Re: A Theoretical Approach

Kim, Synthesis, Characterization, and Spectroscopic Analysis of Antiaromatic Benzofused Metalloporphyrins, Chem.

Computational Study on the Effect of Axial Ligation Upon the Electronic Structure of Copper (II) Porphyrinate (CuTPPs = [5,10,15,20-tetrakis(N-methylpyridyl-4)porhinato]copper(II)tetratosylate)) - Electronic Structure with Different Axial Ligands

They're classified as antiaromatic molecules, which chemical theory predicts will be extremely reactive--in contrast to aromatics, such as benzene, which have unusually stable structures.

Unlikely ion made in lab. (Organic Chemistry)

The cyclopentadienyl cation is a common textbook example of an antiaromatic molecule, a molecule so electronically unstable and, therefore, extremely reactive that it should not exist for any length of time.

Chemists discover molecule considered too unstable to exist. (News Briefs/Nouvelles en Bref)