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Halogen Bonding Involving CO and CS with Carbon as the Electron Donor
MP2/aug’-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH(2). CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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MDPI
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150174/ https://www.ncbi.nlm.nih.gov/pubmed/29137153 http://dx.doi.org/10.3390/molecules22111955 |
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author | Del Bene, Janet E. Alkorta, Ibon Elguero, José |
author_facet | Del Bene, Janet E. Alkorta, Ibon Elguero, José |
author_sort | Del Bene, Janet E. |
collection | PubMed |
description | MP2/aug’-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH(2). CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form traditional halogen-bonded complexes with SC, except ClF which forms only an ion-pair complex. Ion-pair complexes are also found on the SC:ClNC and SC:ClCl surfaces. SC:ClY complexes stabilized by traditional halogen bonds have greater binding energies than the corresponding OC:ClY complexes. The largest binding energies are found for the ion-pair SC–Cl(+):(−)Y complexes. The transition structures which connect the complex and the ion pair on SC:ClNC and SC:ClCl potential surfaces provide the barriers for inter-converting these structures. Charge-transfer from the lone pair on C to the σ-hole on Cl is the primary charge-transfer interaction stabilizing OC:ClY and SC:ClY complexes with traditional halogen bonds. A secondary charge-transfer occurs from the lone pairs on Cl to the in-plane and out-of-plane π antibonding orbitals of ClY. This secondary interaction assumes increased importance in the SC:ClNH(2) complex, and is a factor leading to its unusual structure. C–O and C–S stretching frequencies and (13)C chemical shieldings increase upon complex formation with ClY molecules. These two spectroscopic properties clearly differentiate between SC:ClY complexes and SC–Cl(+):(−)Y ion pairs. Spin–spin coupling constants (1x)J(C–Cl) for OC:ClY complexes increase with decreasing distance. As a function of the C–Cl distance, (1x)J(C–Cl) and (1)J(C–Cl) provide a fingerprint of the evolution of the halogen bond from a traditional halogen bond in the complexes, to a chlorine-shared halogen bond in the transition structures, to a covalent bond in the ion pairs. |
format | Online Article Text |
id | pubmed-6150174 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-61501742018-11-13 Halogen Bonding Involving CO and CS with Carbon as the Electron Donor Del Bene, Janet E. Alkorta, Ibon Elguero, José Molecules Article MP2/aug’-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH(2). CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form traditional halogen-bonded complexes with SC, except ClF which forms only an ion-pair complex. Ion-pair complexes are also found on the SC:ClNC and SC:ClCl surfaces. SC:ClY complexes stabilized by traditional halogen bonds have greater binding energies than the corresponding OC:ClY complexes. The largest binding energies are found for the ion-pair SC–Cl(+):(−)Y complexes. The transition structures which connect the complex and the ion pair on SC:ClNC and SC:ClCl potential surfaces provide the barriers for inter-converting these structures. Charge-transfer from the lone pair on C to the σ-hole on Cl is the primary charge-transfer interaction stabilizing OC:ClY and SC:ClY complexes with traditional halogen bonds. A secondary charge-transfer occurs from the lone pairs on Cl to the in-plane and out-of-plane π antibonding orbitals of ClY. This secondary interaction assumes increased importance in the SC:ClNH(2) complex, and is a factor leading to its unusual structure. C–O and C–S stretching frequencies and (13)C chemical shieldings increase upon complex formation with ClY molecules. These two spectroscopic properties clearly differentiate between SC:ClY complexes and SC–Cl(+):(−)Y ion pairs. Spin–spin coupling constants (1x)J(C–Cl) for OC:ClY complexes increase with decreasing distance. As a function of the C–Cl distance, (1x)J(C–Cl) and (1)J(C–Cl) provide a fingerprint of the evolution of the halogen bond from a traditional halogen bond in the complexes, to a chlorine-shared halogen bond in the transition structures, to a covalent bond in the ion pairs. MDPI 2017-11-12 /pmc/articles/PMC6150174/ /pubmed/29137153 http://dx.doi.org/10.3390/molecules22111955 Text en © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Del Bene, Janet E. Alkorta, Ibon Elguero, José Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title | Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title_full | Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title_fullStr | Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title_full_unstemmed | Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title_short | Halogen Bonding Involving CO and CS with Carbon as the Electron Donor |
title_sort | halogen bonding involving co and cs with carbon as the electron donor |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150174/ https://www.ncbi.nlm.nih.gov/pubmed/29137153 http://dx.doi.org/10.3390/molecules22111955 |
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