The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted bas...
- Autores
- Provasi, Patricio Federico; Aucar, Gustavo Adolfo; Sauer, Stephan P. A.
- Año de publicación
- 2001
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The indirect nuclear spin–spin coupling constants of C₂H4, CH₂NH, CH₂O,CH₂O, and CH₂S were investigated by means of correlated ab initio calculations at the level of the second order polarization propagator approximation (SOPPA) and the second order polarization propagator approximation with coupled clustersingles and doubles amplitudes—SOPPA(CCSD) using large basis sets, which are optimized for the calculation of coupling constants. It is found that at the self-consistent-field (SCF) level CH₂NH and CH₂S exhibit triplet instabilities whereas CH₂ CH₂ and CH₂O show triplet quasi-instabilities, which renders the SCF results meaningless. Our best results deviate between 0.3 and 2.7 Hz from the experimental values. We find that although the one-bond C–H and Y–H couplings as well as the two- and three-bond H–H couplings are dominated by the Fermi contact term, significant contributions of the orbital paramagneticand sometimes even spin–dipolar terms are observed for the one-bond C–Y and two-bond C–H and Y–H coupling constants. Similarly the changes in the couplings caused by the electronegativity and the lone pair of Y are mostly due to changes in the Fermi contact (all couplings) and the orbital paramagneticcontribution (C–Y and two-bond Y–H couplings). However, the trend in the changes are neither the same for both terms not for all couplings. In particular, the position of CH₂S in the series varies indicating that either the electronegativity or the lone pairs are the dominating perturbation. Furthermore, small but optimized Gaussian basis sets for the calculation of indirect nuclear spin–spin coupling constants are presented. They were obtained by contraction of the s- and p-type basis functions for C, N, O, and S and of the s-type basis functions for H of the large uncontracted basis sets. Molecular orbital coefficients of self-consistent-field calculations on CH4, NH3, H₂O, H₂S, and H₂ with the uncontracted basis sets were used as contraction coefficients. Applied in the calculation of all coupling constants in C₂H4, CH₂NH, CH₂O, and CH₂S the contraction leads to a maximum basis set error of ∼0.5 Hz.
Fil: Provasi, Patricio Federico. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Aucar, Gustavo Adolfo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Sauer, Stephan P. A.. Universidad de Copenhagen; Dinamarca - Materia
-
Lone Pairs
Nmr
Basis Sets - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/24673
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3498 |
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CONICET Digital (CONICET) |
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The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis setsProvasi, Patricio FedericoAucar, Gustavo AdolfoSauer, Stephan P. A.Lone PairsNmrBasis Setshttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1The indirect nuclear spin–spin coupling constants of C₂H4, CH₂NH, CH₂O,CH₂O, and CH₂S were investigated by means of correlated ab initio calculations at the level of the second order polarization propagator approximation (SOPPA) and the second order polarization propagator approximation with coupled clustersingles and doubles amplitudes—SOPPA(CCSD) using large basis sets, which are optimized for the calculation of coupling constants. It is found that at the self-consistent-field (SCF) level CH₂NH and CH₂S exhibit triplet instabilities whereas CH₂ CH₂ and CH₂O show triplet quasi-instabilities, which renders the SCF results meaningless. Our best results deviate between 0.3 and 2.7 Hz from the experimental values. We find that although the one-bond C–H and Y–H couplings as well as the two- and three-bond H–H couplings are dominated by the Fermi contact term, significant contributions of the orbital paramagneticand sometimes even spin–dipolar terms are observed for the one-bond C–Y and two-bond C–H and Y–H coupling constants. Similarly the changes in the couplings caused by the electronegativity and the lone pair of Y are mostly due to changes in the Fermi contact (all couplings) and the orbital paramagneticcontribution (C–Y and two-bond Y–H couplings). However, the trend in the changes are neither the same for both terms not for all couplings. In particular, the position of CH₂S in the series varies indicating that either the electronegativity or the lone pairs are the dominating perturbation. Furthermore, small but optimized Gaussian basis sets for the calculation of indirect nuclear spin–spin coupling constants are presented. They were obtained by contraction of the s- and p-type basis functions for C, N, O, and S and of the s-type basis functions for H of the large uncontracted basis sets. Molecular orbital coefficients of self-consistent-field calculations on CH4, NH3, H₂O, H₂S, and H₂ with the uncontracted basis sets were used as contraction coefficients. Applied in the calculation of all coupling constants in C₂H4, CH₂NH, CH₂O, and CH₂S the contraction leads to a maximum basis set error of ∼0.5 Hz.Fil: Provasi, Patricio Federico. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aucar, Gustavo Adolfo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sauer, Stephan P. A.. Universidad de Copenhagen; DinamarcaAmerican Institute of Physics2001-07info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/24673Provasi, Patricio Federico; Aucar, Gustavo Adolfo; Sauer, Stephan P. A.; The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets; American Institute of Physics; Journal of Chemical Physics; 115; 3; 7-2001; 1324-13350021-96061089-7690CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/http://aip.scitation.org/doi/pdf/10.1063/1.1379331info:eu-repo/semantics/altIdentifier/doi/10.1063/1.1379331info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:48:40Zoai:ri.conicet.gov.ar:11336/24673instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:48:40.549CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
title |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
spellingShingle |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets Provasi, Patricio Federico Lone Pairs Nmr Basis Sets |
title_short |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
title_full |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
title_fullStr |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
title_full_unstemmed |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
title_sort |
The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets |
dc.creator.none.fl_str_mv |
Provasi, Patricio Federico Aucar, Gustavo Adolfo Sauer, Stephan P. A. |
author |
Provasi, Patricio Federico |
author_facet |
Provasi, Patricio Federico Aucar, Gustavo Adolfo Sauer, Stephan P. A. |
author_role |
author |
author2 |
Aucar, Gustavo Adolfo Sauer, Stephan P. A. |
author2_role |
author author |
dc.subject.none.fl_str_mv |
Lone Pairs Nmr Basis Sets |
topic |
Lone Pairs Nmr Basis Sets |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
The indirect nuclear spin–spin coupling constants of C₂H4, CH₂NH, CH₂O,CH₂O, and CH₂S were investigated by means of correlated ab initio calculations at the level of the second order polarization propagator approximation (SOPPA) and the second order polarization propagator approximation with coupled clustersingles and doubles amplitudes—SOPPA(CCSD) using large basis sets, which are optimized for the calculation of coupling constants. It is found that at the self-consistent-field (SCF) level CH₂NH and CH₂S exhibit triplet instabilities whereas CH₂ CH₂ and CH₂O show triplet quasi-instabilities, which renders the SCF results meaningless. Our best results deviate between 0.3 and 2.7 Hz from the experimental values. We find that although the one-bond C–H and Y–H couplings as well as the two- and three-bond H–H couplings are dominated by the Fermi contact term, significant contributions of the orbital paramagneticand sometimes even spin–dipolar terms are observed for the one-bond C–Y and two-bond C–H and Y–H coupling constants. Similarly the changes in the couplings caused by the electronegativity and the lone pair of Y are mostly due to changes in the Fermi contact (all couplings) and the orbital paramagneticcontribution (C–Y and two-bond Y–H couplings). However, the trend in the changes are neither the same for both terms not for all couplings. In particular, the position of CH₂S in the series varies indicating that either the electronegativity or the lone pairs are the dominating perturbation. Furthermore, small but optimized Gaussian basis sets for the calculation of indirect nuclear spin–spin coupling constants are presented. They were obtained by contraction of the s- and p-type basis functions for C, N, O, and S and of the s-type basis functions for H of the large uncontracted basis sets. Molecular orbital coefficients of self-consistent-field calculations on CH4, NH3, H₂O, H₂S, and H₂ with the uncontracted basis sets were used as contraction coefficients. Applied in the calculation of all coupling constants in C₂H4, CH₂NH, CH₂O, and CH₂S the contraction leads to a maximum basis set error of ∼0.5 Hz. Fil: Provasi, Patricio Federico. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Aucar, Gustavo Adolfo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sauer, Stephan P. A.. Universidad de Copenhagen; Dinamarca |
description |
The indirect nuclear spin–spin coupling constants of C₂H4, CH₂NH, CH₂O,CH₂O, and CH₂S were investigated by means of correlated ab initio calculations at the level of the second order polarization propagator approximation (SOPPA) and the second order polarization propagator approximation with coupled clustersingles and doubles amplitudes—SOPPA(CCSD) using large basis sets, which are optimized for the calculation of coupling constants. It is found that at the self-consistent-field (SCF) level CH₂NH and CH₂S exhibit triplet instabilities whereas CH₂ CH₂ and CH₂O show triplet quasi-instabilities, which renders the SCF results meaningless. Our best results deviate between 0.3 and 2.7 Hz from the experimental values. We find that although the one-bond C–H and Y–H couplings as well as the two- and three-bond H–H couplings are dominated by the Fermi contact term, significant contributions of the orbital paramagneticand sometimes even spin–dipolar terms are observed for the one-bond C–Y and two-bond C–H and Y–H coupling constants. Similarly the changes in the couplings caused by the electronegativity and the lone pair of Y are mostly due to changes in the Fermi contact (all couplings) and the orbital paramagneticcontribution (C–Y and two-bond Y–H couplings). However, the trend in the changes are neither the same for both terms not for all couplings. In particular, the position of CH₂S in the series varies indicating that either the electronegativity or the lone pairs are the dominating perturbation. Furthermore, small but optimized Gaussian basis sets for the calculation of indirect nuclear spin–spin coupling constants are presented. They were obtained by contraction of the s- and p-type basis functions for C, N, O, and S and of the s-type basis functions for H of the large uncontracted basis sets. Molecular orbital coefficients of self-consistent-field calculations on CH4, NH3, H₂O, H₂S, and H₂ with the uncontracted basis sets were used as contraction coefficients. Applied in the calculation of all coupling constants in C₂H4, CH₂NH, CH₂O, and CH₂S the contraction leads to a maximum basis set error of ∼0.5 Hz. |
publishDate |
2001 |
dc.date.none.fl_str_mv |
2001-07 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11336/24673 Provasi, Patricio Federico; Aucar, Gustavo Adolfo; Sauer, Stephan P. A.; The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets; American Institute of Physics; Journal of Chemical Physics; 115; 3; 7-2001; 1324-1335 0021-9606 1089-7690 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/24673 |
identifier_str_mv |
Provasi, Patricio Federico; Aucar, Gustavo Adolfo; Sauer, Stephan P. A.; The effect of lone pairs and electronegativity on the indirect nuclear spin‐spin coupling constants in CH₂X (X=CH₂, NH, O, S): Ab initio calculations using optimized contracted basis sets; American Institute of Physics; Journal of Chemical Physics; 115; 3; 7-2001; 1324-1335 0021-9606 1089-7690 CONICET Digital CONICET |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/http://aip.scitation.org/doi/pdf/10.1063/1.1379331 info:eu-repo/semantics/altIdentifier/doi/10.1063/1.1379331 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
dc.format.none.fl_str_mv |
application/pdf application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
American Institute of Physics |
publisher.none.fl_str_mv |
American Institute of Physics |
dc.source.none.fl_str_mv |
reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
reponame_str |
CONICET Digital (CONICET) |
collection |
CONICET Digital (CONICET) |
instname_str |
Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.name.fl_str_mv |
CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.mail.fl_str_mv |
dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar |
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1844613510550519808 |
score |
13.070432 |