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The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters

The S∴π hemibond (two-center three-electron, 2c-3e, bond) is an attractive interaction between a sulfur atom and π electrons. The S∴π hemibond is of essential importance in understanding chemistry of sulfur radical cations, and its roles in biochemistry have recently attracted much interest. In the...

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Detalles Bibliográficos
Autores principales: Wang, Dandan, Hattori, Keigo, Fujii, Asuka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685351/
https://www.ncbi.nlm.nih.gov/pubmed/31588295
http://dx.doi.org/10.1039/c9sc02476j
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author Wang, Dandan
Hattori, Keigo
Fujii, Asuka
author_facet Wang, Dandan
Hattori, Keigo
Fujii, Asuka
author_sort Wang, Dandan
collection PubMed
description The S∴π hemibond (two-center three-electron, 2c-3e, bond) is an attractive interaction between a sulfur atom and π electrons. The S∴π hemibond is of essential importance in understanding chemistry of sulfur radical cations, and its roles in biochemistry have recently attracted much interest. In the present study, we observe the S∴π hemibond in the simplest model system in the gas phase. Infrared spectroscopy is applied to the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters. In n = 1, the CH stretch and SH stretch bands of the benzene and H(2)S moieties, respectively, are clearly different from those of the neutral molecules but similar to those of the ionic species. These vibrational features show that the positive charge is delocalized over the cluster due to the S∴π hemibond formation. In n = 2–4, the S∴S hemibond and S–π–S multicenter hemibond (three-center five-electron, 3c-5e, bond) can compete with the S∴π hemibond. The observed vibrational features clearly indicate that the S∴S hemibond formation is superior to the S∴π hemibond and S–π–S multicenter hemibond. Calculations of several dispersion-corrected density functionals are compared with the observations. While all the tested functionals qualitatively catch the feature of the S∴π hemibond, the energy order among the isomers of the different hemibond motifs strongly depends on the functionals. These results demonstrate that the [benzene-(H(2)S)(n)](+) clusters can be a benchmark of density functionals to evaluate the sulfur hemibonds.
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spelling pubmed-66853512019-10-04 The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters Wang, Dandan Hattori, Keigo Fujii, Asuka Chem Sci Chemistry The S∴π hemibond (two-center three-electron, 2c-3e, bond) is an attractive interaction between a sulfur atom and π electrons. The S∴π hemibond is of essential importance in understanding chemistry of sulfur radical cations, and its roles in biochemistry have recently attracted much interest. In the present study, we observe the S∴π hemibond in the simplest model system in the gas phase. Infrared spectroscopy is applied to the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters. In n = 1, the CH stretch and SH stretch bands of the benzene and H(2)S moieties, respectively, are clearly different from those of the neutral molecules but similar to those of the ionic species. These vibrational features show that the positive charge is delocalized over the cluster due to the S∴π hemibond formation. In n = 2–4, the S∴S hemibond and S–π–S multicenter hemibond (three-center five-electron, 3c-5e, bond) can compete with the S∴π hemibond. The observed vibrational features clearly indicate that the S∴S hemibond formation is superior to the S∴π hemibond and S–π–S multicenter hemibond. Calculations of several dispersion-corrected density functionals are compared with the observations. While all the tested functionals qualitatively catch the feature of the S∴π hemibond, the energy order among the isomers of the different hemibond motifs strongly depends on the functionals. These results demonstrate that the [benzene-(H(2)S)(n)](+) clusters can be a benchmark of density functionals to evaluate the sulfur hemibonds. Royal Society of Chemistry 2019-06-19 /pmc/articles/PMC6685351/ /pubmed/31588295 http://dx.doi.org/10.1039/c9sc02476j Text en This journal is © The Royal Society of Chemistry 2019 http://creativecommons.org/licenses/by/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0)
spellingShingle Chemistry
Wang, Dandan
Hattori, Keigo
Fujii, Asuka
The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title_full The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title_fullStr The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title_full_unstemmed The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title_short The S∴π hemibond and its competition with the S∴S hemibond in the simplest model system: infrared spectroscopy of the [benzene-(H(2)S)(n)](+) (n = 1–4) radical cation clusters
title_sort s∴π hemibond and its competition with the s∴s hemibond in the simplest model system: infrared spectroscopy of the [benzene-(h(2)s)(n)](+) (n = 1–4) radical cation clusters
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685351/
https://www.ncbi.nlm.nih.gov/pubmed/31588295
http://dx.doi.org/10.1039/c9sc02476j
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