Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect
Autor(a) principal: | |
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Data de Publicação: | 2014 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFLA |
Texto Completo: | http://repositorio.ufla.br/jspui/handle/1/41840 |
Resumo: | The gauche effect in fluorinated alkylammonium salts is well known and attributed either to an intramolecular hydrogen bond or to an electrostatic attraction between the positively charged nitrogen and the vicinal electronegative fluorine atom. This work reports the effect of adding a fluorine atom in 2-fluoroethylamine hydrochloride on the conformational isomerism of the resulting 2,2-difluoroethylamine chloride (2). The analysis was carried out using NMR coupling constants in D2O solution, in order to mimic the equilibrium conditions in a physiological medium, in the gas phase and in implicit water through theoretical calculations. Despite the presence of σCH→σ*CF and σCH→σ*CN interactions, which usually rule the hyperconjugative gauche effect in 1,2-disubstituted ethanes, the most important forces leading to the double gauche effect (+NH3 in the gauche relationship with both fluorine atoms) in 2 are the Lewis-type ones. Particularly, electrostatic interactions are operative even in water solution, where they should be significantly attenuated, whereas hyperconjugation and hydrogen bond have secondary importance. |
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Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effectConformational analysis2,2-difluoroethylamine hydrochlorideGauche effectHydrogen bondingThe gauche effect in fluorinated alkylammonium salts is well known and attributed either to an intramolecular hydrogen bond or to an electrostatic attraction between the positively charged nitrogen and the vicinal electronegative fluorine atom. This work reports the effect of adding a fluorine atom in 2-fluoroethylamine hydrochloride on the conformational isomerism of the resulting 2,2-difluoroethylamine chloride (2). The analysis was carried out using NMR coupling constants in D2O solution, in order to mimic the equilibrium conditions in a physiological medium, in the gas phase and in implicit water through theoretical calculations. Despite the presence of σCH→σ*CF and σCH→σ*CN interactions, which usually rule the hyperconjugative gauche effect in 1,2-disubstituted ethanes, the most important forces leading to the double gauche effect (+NH3 in the gauche relationship with both fluorine atoms) in 2 are the Lewis-type ones. Particularly, electrostatic interactions are operative even in water solution, where they should be significantly attenuated, whereas hyperconjugation and hydrogen bond have secondary importance.Beilstein-Institut2020-07-12T23:34:52Z2020-07-12T23:34:52Z2014-04-16info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfSILLA, J. M. et al. Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect. Beilstein Journal of Organic Chemistry, [S.l.], v. 10, p. 877-882, Apr. 2014. DOI: 10.3762/bjoc.10.84.http://repositorio.ufla.br/jspui/handle/1/41840Beilstein Journal of Organic Chemistryreponame:Repositório Institucional da UFLAinstname:Universidade Federal de Lavras (UFLA)instacron:UFLAAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessSilla, Josué M.Duarte, Claudimar J.Cormanich, Rodrigo A.Rittner, RobertoFreitas, Matheus P.eng2020-07-12T23:34:52Zoai:localhost:1/41840Repositório InstitucionalPUBhttp://repositorio.ufla.br/oai/requestnivaldo@ufla.br || repositorio.biblioteca@ufla.bropendoar:2020-07-12T23:34:52Repositório Institucional da UFLA - Universidade Federal de Lavras (UFLA)false |
dc.title.none.fl_str_mv |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
title |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
spellingShingle |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect Silla, Josué M. Conformational analysis 2,2-difluoroethylamine hydrochloride Gauche effect Hydrogen bonding |
title_short |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
title_full |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
title_fullStr |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
title_full_unstemmed |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
title_sort |
Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect |
author |
Silla, Josué M. |
author_facet |
Silla, Josué M. Duarte, Claudimar J. Cormanich, Rodrigo A. Rittner, Roberto Freitas, Matheus P. |
author_role |
author |
author2 |
Duarte, Claudimar J. Cormanich, Rodrigo A. Rittner, Roberto Freitas, Matheus P. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Silla, Josué M. Duarte, Claudimar J. Cormanich, Rodrigo A. Rittner, Roberto Freitas, Matheus P. |
dc.subject.por.fl_str_mv |
Conformational analysis 2,2-difluoroethylamine hydrochloride Gauche effect Hydrogen bonding |
topic |
Conformational analysis 2,2-difluoroethylamine hydrochloride Gauche effect Hydrogen bonding |
description |
The gauche effect in fluorinated alkylammonium salts is well known and attributed either to an intramolecular hydrogen bond or to an electrostatic attraction between the positively charged nitrogen and the vicinal electronegative fluorine atom. This work reports the effect of adding a fluorine atom in 2-fluoroethylamine hydrochloride on the conformational isomerism of the resulting 2,2-difluoroethylamine chloride (2). The analysis was carried out using NMR coupling constants in D2O solution, in order to mimic the equilibrium conditions in a physiological medium, in the gas phase and in implicit water through theoretical calculations. Despite the presence of σCH→σ*CF and σCH→σ*CN interactions, which usually rule the hyperconjugative gauche effect in 1,2-disubstituted ethanes, the most important forces leading to the double gauche effect (+NH3 in the gauche relationship with both fluorine atoms) in 2 are the Lewis-type ones. Particularly, electrostatic interactions are operative even in water solution, where they should be significantly attenuated, whereas hyperconjugation and hydrogen bond have secondary importance. |
publishDate |
2014 |
dc.date.none.fl_str_mv |
2014-04-16 2020-07-12T23:34:52Z 2020-07-12T23:34:52Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
SILLA, J. M. et al. Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect. Beilstein Journal of Organic Chemistry, [S.l.], v. 10, p. 877-882, Apr. 2014. DOI: 10.3762/bjoc.10.84. http://repositorio.ufla.br/jspui/handle/1/41840 |
identifier_str_mv |
SILLA, J. M. et al. Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect. Beilstein Journal of Organic Chemistry, [S.l.], v. 10, p. 877-882, Apr. 2014. DOI: 10.3762/bjoc.10.84. |
url |
http://repositorio.ufla.br/jspui/handle/1/41840 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Beilstein-Institut |
publisher.none.fl_str_mv |
Beilstein-Institut |
dc.source.none.fl_str_mv |
Beilstein Journal of Organic Chemistry reponame:Repositório Institucional da UFLA instname:Universidade Federal de Lavras (UFLA) instacron:UFLA |
instname_str |
Universidade Federal de Lavras (UFLA) |
instacron_str |
UFLA |
institution |
UFLA |
reponame_str |
Repositório Institucional da UFLA |
collection |
Repositório Institucional da UFLA |
repository.name.fl_str_mv |
Repositório Institucional da UFLA - Universidade Federal de Lavras (UFLA) |
repository.mail.fl_str_mv |
nivaldo@ufla.br || repositorio.biblioteca@ufla.br |
_version_ |
1807835104987316224 |