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Molecular Orbital Theory II03:51

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The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
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Published on: April 19, 2019

Clar theory for molecular benzenoids.

Anirban Misra1, D J Klein, T Morikawa

  • 1Texas A&M University at Galveston, MARS, 5007 Avenue U, Texas 77551, USA. anirbanmisra@yahoo.com

The Journal of Physical Chemistry. A
|January 10, 2009
PubMed
Summary
This summary is machine-generated.

This study introduces the Clar 2-nomial, a quantitative method to analyze aromatic sextets. This new polynomial successfully correlates with key aromaticity indicators like resonance energies and NICS values.

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Area of Science:

  • * Organic Chemistry
  • * Theoretical Chemistry

Background:

  • * Eric Clar's concept of "aromatic sextets" is fundamental to understanding aromaticity in polycyclic aromatic hydrocarbons.
  • * Existing methods for quantifying aromaticity can be complex and may not fully capture nuanced electronic properties.

Purpose of the Study:

  • * To develop a quantitative polynomial, the "Clar 2-nomial", extending Eric Clar's aromatic sextet theory.
  • * To establish a novel computational tool for assessing aromaticity in chemical systems.
  • * To validate the Clar 2-nomial against established experimental and computational data.

Main Methods:

  • * Development of a polynomial expression, the "Clar 2-nomial", based on Clar's aromatic sextet rules.
  • * Calculation of derivative quantities from the Clar 2-nomial.
  • * Correlation analysis with existing numerical data sets.

Main Results:

  • * The Clar 2-nomial provides a successful quantitative measure of aromaticity.
  • * Strong correlations were observed between Clar 2-nomial values and resonance energies.
  • * The polynomial also showed good agreement with bond length data and Nuclear Independent Chemical Shift (NICS) ring-aromaticity values.

Conclusions:

  • * The Clar 2-nomial offers a robust and accessible method for quantifying aromaticity.
  • * This approach provides valuable insights into the electronic structure and stability of aromatic compounds.
  • * The Clar 2-nomial serves as a promising tool for future research in aromaticity studies.