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The role of quantum-mechanical interference and quasi-classical effects in conjugated hydrocarbons

Fantuzzi, Felipe, Cardozo, Thiago Messias, Chaer Nascimento, Marco Antonio (2012) The role of quantum-mechanical interference and quasi-classical effects in conjugated hydrocarbons. Physical Chemistry Chemical Physics, 14 . pp. 5479-5488. ISSN 1463-9076. E-ISSN 1463-9084. (doi:10.1039/C2CP24125K) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:98580)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided.
Official URL:
https://doi.org/10.1039/C2CP24125K

Abstract

The nature of the chemical bond in conjugated hydrocarbons is analyzed through the generalized product function energy partitioning (GPF-EP) method, which allows the calculation of the quantum-mechanical interference and quasi-classical contributions to the energy. The method is applied to investigate the differences between the chemical bonding in conjugated and non-conjugated hydrocarbon isomers and to evaluate the contribution from the energy components to the stabilization of the molecules. It is shown that in all cases quantum-mechanical interference has the effect of concentrating π electron density between the two carbon atoms directly involved in the (C–C)π bonds. For the conjugated isomers, this effect is accompanied by a substantial reduction of electron density in the π space of the neighbouring (C–C)σ bond. On the other hand, quasi-classical effects are shown to be responsible for the extra stabilization of the conjugated isomers, in which a decrease of the π space kinetic reference energy seems to play an important role. Finally, it is shown that the polarization of p-like orbitals in compounds with alternating single and double bonds ultimately increases electron density in the π space of the neighbouring (C–C)σ bond. Therefore, quasi-classical effects, rather than covalent ones, seem to be responsible for several properties of conjugated molecules, such as thermodynamic stability, planarity and (C–C)σ bond shortening. The shortcomings of the delocalization concept are discussed.

Item Type: Article
DOI/Identification number: 10.1039/C2CP24125K
Subjects: Q Science > QD Chemistry
Divisions: Divisions > Division of Natural Sciences > Chemistry and Forensics
Funders: Coordenação de Aperfeicoamento de Pessoal de Nível Superior (https://ror.org/00x0ma614)
National Council for Scientific and Technological Development (https://ror.org/03swz6y49)
Depositing User: Felipe Fantuzzi
Date Deposited: 01 Dec 2022 00:19 UTC
Last Modified: 02 Dec 2022 09:10 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/98580 (The current URI for this page, for reference purposes)

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