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
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/24673

id CONICETDig_8755b5d8cf61231f024f7ba7b0d5935e
oai_identifier_str oai:ri.conicet.gov.ar:11336/24673
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling 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
_version_ 1844613510550519808
score 13.070432