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  2. Antiaromaticity - Wikipedia

    en.wikipedia.org/wiki/Antiaromaticity

    In this section, only examples of antiaromatic compounds which are non-disputable are included. Pentalene is an antiaromatic compound which has been well-studied both experimentally and computationally for decades. It is dicyclic, planar and has eight π-electrons, fulfilling the IUPAC definition of antiaromaticity.

  3. Annulene - Wikipedia

    en.wikipedia.org/wiki/Annulene

    Annulenes may be aromatic (benzene, [6]annulene and [18]annulene), non-aromatic ([8] and [10]annulene), or anti-aromatic (cyclobutadiene, [4]annulene). Cyclobutadiene is the only annulene with considerable antiaromaticity, since planarity is unavoidable.

  4. Category:Antiaromatic compounds - Wikipedia

    en.wikipedia.org/.../Category:Antiaromatic_compounds

    Pages in category "Antiaromatic compounds" The following 13 pages are in this category, out of 13 total. This list may not reflect recent changes. ...

  5. Möbius aromaticity - Wikipedia

    en.wikipedia.org/wiki/Möbius_aromaticity

    In contrast to the rarity of Möbius aromatic ground state molecular systems, there are many examples of pericyclic transition states that exhibit Möbius aromaticity. The classification of a pericyclic transition state as either Möbius or Hückel topology determines whether 4N or 4N + 2 electrons are required to make the transition state aromatic or antiaromatic, and therefore, allowed or ...

  6. Conjugated system - Wikipedia

    en.wikipedia.org/wiki/Conjugated_system

    Cinnamaldehyde is a naturally-occurring compound that has a conjugated system penta-1,3-diene is a molecule with a conjugated system Diazomethane conjugated pi-system. In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability.

  7. Cyclooctatetraene - Wikipedia

    en.wikipedia.org/wiki/Cyclooctatetraene

    Early studies demonstrated that COT did not display the chemistry of an aromatic compound. [7] Then, early electron diffraction experiments concluded that the C-C bond distances were identical. [ 8 ] However, X-ray diffraction data from H. S. Kaufman demonstrated cyclooctatetraene to adopt several conformations and to contain two distinct C–C ...

  8. Homoaromaticity - Wikipedia

    en.wikipedia.org/wiki/Homoaromaticity

    Homoaromaticity, in organic chemistry, refers to a special case of aromaticity in which conjugation is interrupted by a single sp 3 hybridized carbon atom. Although this sp 3 center disrupts the continuous overlap of p-orbitals, traditionally thought to be a requirement for aromaticity, considerable thermodynamic stability and many of the spectroscopic, magnetic, and chemical properties ...

  9. Quinone - Wikipedia

    en.wikipedia.org/wiki/Quinone

    An example of 1,4-addition reaction is the addition of hydrogen chloride to form chlorohydroquinone: 1,4-addition reaction of quinone with hydrogen chloride to produce chlorohydroquinone. Quinones can undergo Diels–Alder reactions. [10] The quinone acts as the dienophile and reacts with a diene at a carbon-carbon double bond.