Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFLA |
Texto Completo: | http://repositorio.ufla.br/jspui/handle/1/33606 |
Resumo: | Long-range coupling studies 4JH2,H6were performed for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). NBO calculations and coupling constants were performed with the objective of evaluating the effect of the halogen and electron acceptor character of the *orbital on the said coupling constants. The results pointed to hyperconjugative interactionsC2H2→*C1=YandC6H6→*C1=Y (Y = O and S) for the equatorial forms of the compounds replaced by F, Cl and Br, which probably contribute to the mechanism of transmission of4JH2,H6. The interactionsC2H2→*C1=YandC6H6→*C1=Y are higher for thiocarbonyl compounds, but the values of 4JH2,H6are higher for the carbonyl compounds. This is because the term Fermi (FC), which is influenced by the character of bonding lengths between the atoms involved in the coupling pathway, for thiocarbonyl compounds undergoes a larger decay than for the ketones, reducing the value of4JH2,H6. The implied solvent effect (DMSO and water) at the values of the coupling constant was insignificant when compared to the gas phase. On the other hand, the effect of the explicit solvent on 4JH2,H6was more sensitive for thiocarbonyl compounds than for cyclohexanones. The different halogens do not affect the magnitude of4JH2,H6. Also performed were Perlin effect studies for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). The Perlin effect is an NMR phenomenon observed in six-membered rings and is referred to as 1JC-Hax <1JC-Heq. In this work, the influence of halogens (F, Cl and Br) at position 2 in cyclohexanones and cyclohexanthiones is theoretically evaluated in the C2 - H2 coupling constants of a bond, i.e. in the Perlin effect. An important hyperconjugative interaction (C=Y→*C-H, Y = O e S) operating in the systems studied seems to play a significant role for the observed behavior of 1JC-Hax <1JC-Heq. In addition, the contribution of Lewis (1JLewis) dominates the Fermi Contact term (1JFC), which plays the leading role for the C-H coupling constant of a general bond. In comparison with the gas phase, this behavior was considered insensitive to implicit solvents (DMSO and water). |
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Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effectsSondando a constante de acoplamento spin-spin em 2-halocicloexanonas e 2-halociclotioexanonas: o papel do efeito perlin, solvente e estereoeletrônicoLong-range coupling4 JH2,H6Perlin effectHyperconjugationAcoplamento de longo alcanceEfeito PerlinHiperconjugaçãoBioquímicaLong-range coupling studies 4JH2,H6were performed for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). NBO calculations and coupling constants were performed with the objective of evaluating the effect of the halogen and electron acceptor character of the *orbital on the said coupling constants. The results pointed to hyperconjugative interactionsC2H2→*C1=YandC6H6→*C1=Y (Y = O and S) for the equatorial forms of the compounds replaced by F, Cl and Br, which probably contribute to the mechanism of transmission of4JH2,H6. The interactionsC2H2→*C1=YandC6H6→*C1=Y are higher for thiocarbonyl compounds, but the values of 4JH2,H6are higher for the carbonyl compounds. This is because the term Fermi (FC), which is influenced by the character of bonding lengths between the atoms involved in the coupling pathway, for thiocarbonyl compounds undergoes a larger decay than for the ketones, reducing the value of4JH2,H6. The implied solvent effect (DMSO and water) at the values of the coupling constant was insignificant when compared to the gas phase. On the other hand, the effect of the explicit solvent on 4JH2,H6was more sensitive for thiocarbonyl compounds than for cyclohexanones. The different halogens do not affect the magnitude of4JH2,H6. Also performed were Perlin effect studies for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). The Perlin effect is an NMR phenomenon observed in six-membered rings and is referred to as 1JC-Hax <1JC-Heq. In this work, the influence of halogens (F, Cl and Br) at position 2 in cyclohexanones and cyclohexanthiones is theoretically evaluated in the C2 - H2 coupling constants of a bond, i.e. in the Perlin effect. An important hyperconjugative interaction (C=Y→*C-H, Y = O e S) operating in the systems studied seems to play a significant role for the observed behavior of 1JC-Hax <1JC-Heq. In addition, the contribution of Lewis (1JLewis) dominates the Fermi Contact term (1JFC), which plays the leading role for the C-H coupling constant of a general bond. In comparison with the gas phase, this behavior was considered insensitive to implicit solvents (DMSO and water).Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Estudos de acoplamento de longo alcance 4JH2,H6 foram realizados para 2-halo-cicloexanonas e cicloexanotionas substituídas por (F, Cl e Br). Cálculos de NBO e constantes de acoplamento foram realizados com o objetivo de se avaliar o efeito do halogênio e do caráter aceptor de elétrons do orbital * sobre as referidas constantes de acoplamento. Os resultados apontaram interações hiperconjugativasC2H2→*C1=Y e C6H6→*C1=Y (Y = O e S) para as formas equatoriais dos compostos substituídos por F, Cl e Br, as quais provavelmente contribuem para o mecanismo de transmissão de 4JH2,H6. As interações C2H2→*C=Se C6H6→*C=S são maiores para os compostos tiocarbonílicos, porém os valores de 4JH2,H6são maiores para os compostos carbonílicos. Isso acontece porque o termo contato de Fermi (FC), que é influenciado pelo caráter s e comprimentos de ligação entre os átomos envolvidos na via de acoplamento, para os compostos tiocarbonílicos sofre um decaimento maior do que para as cetonas, reduzindo o valor de 4J¬H2,H6.O efeito solvente implícito (DMSO e água) nos valores da constante de acoplamento foi insignificante quando comparado com a fase gasosa. Por outro lado, o efeito do solvente explícito em 4JH2,H6foi mais sensível para os compostos tiocarbonílicosdo que para as ciclohexanonas.Os diferentes halogênios não afetam a magnitude de 4JH2,H6. Também foram efetuados estudos do efeito Perlin para 2-halo-cicloexanonas e cicloexanotionas substituídas por (F, Cl e Br). O efeito Perlin é um fenômeno de RMN observado em anéis de seis membros e é referido como1JC−Hax<1JC−Heq. Neste presente trabalho, a influência de halogênios (F, Cl e Br) na posição 2 em ciclohexanonas e ciclohexanotionas é avaliada teoricamente nas constantes de acoplamento C2 − H2 de uma ligação, ou seja, no efeito Perlin. Uma interação hiperconjugativa importante (C=Y→*C-H, Y = O e S) operando nos sistemas estudados parece desempenhar um papel significativo para o comportamento observado 1JC−Hax<1JC−Heq. Além disso, a contribuição de Lewis (JLewis) domina o termo de Contato Fermi (JFC), que desempenha o papel principal para a constante de acoplamento C-H de uma ligação geral. Em comparação com a fase gasosa, este comportamento foi considerado insensível a solventes implícitos (DMSO e água).Universidade Federal de LavrasPrograma de Pós-graduação em AgroquímicaUFLAbrasilDepartamento de QuímicaRamalho, Teodorico de CastroFreitas, Matheus Puggina dePacheco, Alison GeraldoAlmeida, Kátia Júlia deCosta, Luiz Antônio SodréThomasi, Sérgio SherrerRezende, Fátima Maria Pereira de2019-04-17T13:20:10Z2019-04-17T13:20:10Z2019-04-162019-02-18info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfREZENDE, F. M. P. de. Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects. 2019. 85 p. Tese (Doutorado em Agroquímica)–Universidade Federal de Lavras, Lavras, 2019.http://repositorio.ufla.br/jspui/handle/1/33606enginfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFLAinstname:Universidade Federal de Lavras (UFLA)instacron:UFLA2019-04-17T13:20:10Zoai:localhost:1/33606Repositório InstitucionalPUBhttp://repositorio.ufla.br/oai/requestnivaldo@ufla.br || repositorio.biblioteca@ufla.bropendoar:2019-04-17T13:20:10Repositório Institucional da UFLA - Universidade Federal de Lavras (UFLA)false |
dc.title.none.fl_str_mv |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects Sondando a constante de acoplamento spin-spin em 2-halocicloexanonas e 2-halociclotioexanonas: o papel do efeito perlin, solvente e estereoeletrônico |
title |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
spellingShingle |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects Rezende, Fátima Maria Pereira de Long-range coupling 4 JH2,H6 Perlin effect Hyperconjugation Acoplamento de longo alcance Efeito Perlin Hiperconjugação Bioquímica |
title_short |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
title_full |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
title_fullStr |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
title_full_unstemmed |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
title_sort |
Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects |
author |
Rezende, Fátima Maria Pereira de |
author_facet |
Rezende, Fátima Maria Pereira de |
author_role |
author |
dc.contributor.none.fl_str_mv |
Ramalho, Teodorico de Castro Freitas, Matheus Puggina de Pacheco, Alison Geraldo Almeida, Kátia Júlia de Costa, Luiz Antônio Sodré Thomasi, Sérgio Sherrer |
dc.contributor.author.fl_str_mv |
Rezende, Fátima Maria Pereira de |
dc.subject.por.fl_str_mv |
Long-range coupling 4 JH2,H6 Perlin effect Hyperconjugation Acoplamento de longo alcance Efeito Perlin Hiperconjugação Bioquímica |
topic |
Long-range coupling 4 JH2,H6 Perlin effect Hyperconjugation Acoplamento de longo alcance Efeito Perlin Hiperconjugação Bioquímica |
description |
Long-range coupling studies 4JH2,H6were performed for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). NBO calculations and coupling constants were performed with the objective of evaluating the effect of the halogen and electron acceptor character of the *orbital on the said coupling constants. The results pointed to hyperconjugative interactionsC2H2→*C1=YandC6H6→*C1=Y (Y = O and S) for the equatorial forms of the compounds replaced by F, Cl and Br, which probably contribute to the mechanism of transmission of4JH2,H6. The interactionsC2H2→*C1=YandC6H6→*C1=Y are higher for thiocarbonyl compounds, but the values of 4JH2,H6are higher for the carbonyl compounds. This is because the term Fermi (FC), which is influenced by the character of bonding lengths between the atoms involved in the coupling pathway, for thiocarbonyl compounds undergoes a larger decay than for the ketones, reducing the value of4JH2,H6. The implied solvent effect (DMSO and water) at the values of the coupling constant was insignificant when compared to the gas phase. On the other hand, the effect of the explicit solvent on 4JH2,H6was more sensitive for thiocarbonyl compounds than for cyclohexanones. The different halogens do not affect the magnitude of4JH2,H6. Also performed were Perlin effect studies for 2-halo-cyclohexanones and cyclohexanthiones substituted by (F, Cl and Br). The Perlin effect is an NMR phenomenon observed in six-membered rings and is referred to as 1JC-Hax <1JC-Heq. In this work, the influence of halogens (F, Cl and Br) at position 2 in cyclohexanones and cyclohexanthiones is theoretically evaluated in the C2 - H2 coupling constants of a bond, i.e. in the Perlin effect. An important hyperconjugative interaction (C=Y→*C-H, Y = O e S) operating in the systems studied seems to play a significant role for the observed behavior of 1JC-Hax <1JC-Heq. In addition, the contribution of Lewis (1JLewis) dominates the Fermi Contact term (1JFC), which plays the leading role for the C-H coupling constant of a general bond. In comparison with the gas phase, this behavior was considered insensitive to implicit solvents (DMSO and water). |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019-04-17T13:20:10Z 2019-04-17T13:20:10Z 2019-04-16 2019-02-18 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
REZENDE, F. M. P. de. Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects. 2019. 85 p. Tese (Doutorado em Agroquímica)–Universidade Federal de Lavras, Lavras, 2019. http://repositorio.ufla.br/jspui/handle/1/33606 |
identifier_str_mv |
REZENDE, F. M. P. de. Probing spin-spin coupling constants in 2-halocyclohexanones and 2-halocyclohexanothiones: the role of the perlin, solvent and stereoelectronic effects. 2019. 85 p. Tese (Doutorado em Agroquímica)–Universidade Federal de Lavras, Lavras, 2019. |
url |
http://repositorio.ufla.br/jspui/handle/1/33606 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Lavras Programa de Pós-graduação em Agroquímica UFLA brasil Departamento de Química |
publisher.none.fl_str_mv |
Universidade Federal de Lavras Programa de Pós-graduação em Agroquímica UFLA brasil Departamento de Química |
dc.source.none.fl_str_mv |
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_ |
1807835109728976896 |