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Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions
Benzene dimer has long been an archetype for π-stacking. According to the Hunter–Sanders model, quadrupolar electrostatics favors an edge-to-face CH⋯π geometry but competes with London dispersion that favors cofacial π-stacking, with a compromise “slip-stacked” structure emerging as the minimum-ener...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8159364/ https://www.ncbi.nlm.nih.gov/pubmed/34094127 http://dx.doi.org/10.1039/d0sc02667k |
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author | Carter-Fenk, Kevin Herbert, John M. |
author_facet | Carter-Fenk, Kevin Herbert, John M. |
author_sort | Carter-Fenk, Kevin |
collection | PubMed |
description | Benzene dimer has long been an archetype for π-stacking. According to the Hunter–Sanders model, quadrupolar electrostatics favors an edge-to-face CH⋯π geometry but competes with London dispersion that favors cofacial π-stacking, with a compromise “slip-stacked” structure emerging as the minimum-energy geometry. This model is based on classical electrostatics, however, and neglects charge penetration. A fully quantum-mechanical analysis, presented here, demonstrates that electrostatics actually exerts very little influence on the conformational landscape of (C(6)H(6))(2). Electrostatics also cannot explain the slip-stacked arrangement of C(6)H(6)⋯C(6)F(6), where the sign of the quadrupolar interaction is reversed. Instead, the slip-stacked geometry emerges in both systems due to competition between dispersion and Pauli repulsion, with electrostatics as an ambivalent spectator. This revised interpretation helps to rationalize the persistence of offset π-stacking in larger polycyclic aromatic hydrocarbons and across the highly varied electrostatic environments that characterize π–π interactions in proteins. |
format | Online Article Text |
id | pubmed-8159364 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-81593642021-06-04 Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions Carter-Fenk, Kevin Herbert, John M. Chem Sci Chemistry Benzene dimer has long been an archetype for π-stacking. According to the Hunter–Sanders model, quadrupolar electrostatics favors an edge-to-face CH⋯π geometry but competes with London dispersion that favors cofacial π-stacking, with a compromise “slip-stacked” structure emerging as the minimum-energy geometry. This model is based on classical electrostatics, however, and neglects charge penetration. A fully quantum-mechanical analysis, presented here, demonstrates that electrostatics actually exerts very little influence on the conformational landscape of (C(6)H(6))(2). Electrostatics also cannot explain the slip-stacked arrangement of C(6)H(6)⋯C(6)F(6), where the sign of the quadrupolar interaction is reversed. Instead, the slip-stacked geometry emerges in both systems due to competition between dispersion and Pauli repulsion, with electrostatics as an ambivalent spectator. This revised interpretation helps to rationalize the persistence of offset π-stacking in larger polycyclic aromatic hydrocarbons and across the highly varied electrostatic environments that characterize π–π interactions in proteins. The Royal Society of Chemistry 2020-06-05 /pmc/articles/PMC8159364/ /pubmed/34094127 http://dx.doi.org/10.1039/d0sc02667k Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/ |
spellingShingle | Chemistry Carter-Fenk, Kevin Herbert, John M. Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title | Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title_full | Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title_fullStr | Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title_full_unstemmed | Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title_short | Electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
title_sort | electrostatics does not dictate the slip-stacked arrangement of aromatic π–π interactions |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8159364/ https://www.ncbi.nlm.nih.gov/pubmed/34094127 http://dx.doi.org/10.1039/d0sc02667k |
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