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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Autor principal: Contreras, Rubén Horacio
Publicado: 2006
Materias:
Chemical bonds
Electric charge
Electrostatics
Mathematical models
Nuclear magnetic resonance
Nuclear physics
Hyperconjugation
Nucleus
Point charge
Scalar couplings
Molecular physics
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v110_n12_p4266_Contreras
http://hdl.handle.net/20.500.12110/paper_10895639_v110_n12_p4266_Contreras
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_10895639_v110_n12_p4266_Contreras2023-06-08T16:06:21Z Experimental and theoretical study of hyperconjugative interaction effects on NMR1JCH scalar couplings Contreras, Rubén Horacio 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. 2006 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v110_n12_p4266_Contreras 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, Rubén Horacio
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.
author Contreras, Rubén Horacio
author_facet Contreras, Rubén Horacio
author_sort Contreras, Rubén Horacio
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
publishDate 2006
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v110_n12_p4266_Contreras
http://hdl.handle.net/20.500.12110/paper_10895639_v110_n12_p4266_Contreras
work_keys_str_mv AT contrerasrubenhoracio experimentalandtheoreticalstudyofhyperconjugativeinteractioneffectsonnmr1jchscalarcouplings
_version_ 1768545522420809728

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