Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings

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Hyperconjugative and electrostatic interactions effects on 1JCH spin-spin coupling constants (SSCCs) are critically studied from both theoretical and experimental points of view. A qualitative model is used to predict how the former affect such SSCCs, while electrostatic interactions are modeled wit...

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Autores principales: Contreras, R.H., Esteban, Á.L., Díez, E., Della, E.W., Lochert, I.J., Dos Santos, F.P., Tormena, C.F.
Formato: JOUR
Materias:
Chemical bonds
Electric charge
Electrostatics
Mathematical models
Nuclear magnetic resonance
Nuclear physics
Hyperconjugation
Nucleus
Point charge
Scalar couplings
Molecular physics
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_10895639_v110_n12_p4266_Contreras
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_10895639_v110_n12_p4266_Contreras
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spelling todo:paper_10895639_v110_n12_p4266_Contreras2023-10-03T16:04:34Z Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings Contreras, R.H. Esteban, Á.L. Díez, E. Della, E.W. Lochert, I.J. Dos Santos, F.P. Tormena, C.F. Chemical bonds Electric charge Electrostatics Mathematical models Nuclear magnetic resonance Nuclear physics Hyperconjugation Nucleus Point charge Scalar couplings Molecular physics Hyperconjugative and electrostatic interactions effects on 1JCH spin-spin coupling constants (SSCCs) are critically studied from both theoretical and experimental points of view. A qualitative model is used to predict how the former affect such SSCCs, while electrostatic interactions are modeled with a point charge placed in the vicinity of the corresponding σCH bond. Hyperconjugative interactions are calculated using the "natural bond orbital" approach, and using the point-charge model, it is shown how intertwined are both types of interactions. Several members of the series 1-X-bicyclo[1.1.1]pentane and 1-X-3- methylbicyclo[1.1.1]pentane are chosen as model compounds for measuring 1JCH SSCCs; in some of them were performed also DFT-SSCC calculations. The strained cage substrate in these series defines strong σ-hyperconjugative interactions, making these compounds excellent examples to verify the qualitative model presented in this work. It is verified that (a) hyperconjugative interactions from the σCH bond or into the σ*CH antibond containing the coupling nuclei yield a decrease of the corresponding 1JCH SSCC and (b) hyperconjugative interactions from other bonds involving the coupling C nucleus yield an increase of that 1JCH SSCC. © 2006 American Chemical Society. Fil:Contreras, R.H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_10895639_v110_n12_p4266_Contreras
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Chemical bonds
Electric charge
Electrostatics
Mathematical models
Nuclear magnetic resonance
Nuclear physics
Hyperconjugation
Nucleus
Point charge
Scalar couplings
Molecular physics
spellingShingle Chemical bonds
Electric charge
Electrostatics
Mathematical models
Nuclear magnetic resonance
Nuclear physics
Hyperconjugation
Nucleus
Point charge
Scalar couplings
Molecular physics
Contreras, R.H.
Esteban, Á.L.
Díez, E.
Della, E.W.
Lochert, I.J.
Dos Santos, F.P.
Tormena, C.F.
Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
topic_facet Chemical bonds
Electric charge
Electrostatics
Mathematical models
Nuclear magnetic resonance
Nuclear physics
Hyperconjugation
Nucleus
Point charge
Scalar couplings
Molecular physics
description Hyperconjugative and electrostatic interactions effects on 1JCH spin-spin coupling constants (SSCCs) are critically studied from both theoretical and experimental points of view. A qualitative model is used to predict how the former affect such SSCCs, while electrostatic interactions are modeled with a point charge placed in the vicinity of the corresponding σCH bond. Hyperconjugative interactions are calculated using the "natural bond orbital" approach, and using the point-charge model, it is shown how intertwined are both types of interactions. Several members of the series 1-X-bicyclo[1.1.1]pentane and 1-X-3- methylbicyclo[1.1.1]pentane are chosen as model compounds for measuring 1JCH SSCCs; in some of them were performed also DFT-SSCC calculations. The strained cage substrate in these series defines strong σ-hyperconjugative interactions, making these compounds excellent examples to verify the qualitative model presented in this work. It is verified that (a) hyperconjugative interactions from the σCH bond or into the σ*CH antibond containing the coupling nuclei yield a decrease of the corresponding 1JCH SSCC and (b) hyperconjugative interactions from other bonds involving the coupling C nucleus yield an increase of that 1JCH SSCC. © 2006 American Chemical Society.
format JOUR
author Contreras, R.H.
Esteban, Á.L.
Díez, E.
Della, E.W.
Lochert, I.J.
Dos Santos, F.P.
Tormena, C.F.
author_facet Contreras, R.H.
Esteban, Á.L.
Díez, E.
Della, E.W.
Lochert, I.J.
Dos Santos, F.P.
Tormena, C.F.
author_sort Contreras, R.H.
title Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
title_short Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
title_full Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
title_fullStr Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
title_full_unstemmed Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings
title_sort experimental and theoretical study of hyperconjugative interaction effects on nmr1jch scalar couplings
url http://hdl.handle.net/20.500.12110/paper_10895639_v110_n12_p4266_Contreras
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