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dc.creatorRezende, Fátima M. P. de-
dc.creatorFreitas, Matheus P.-
dc.creatorRamalho, Teodorico C.-
dc.date.accessioned2019-05-30T19:42:02Z-
dc.date.available2019-05-30T19:42:02Z-
dc.date.issued2018-09-
dc.identifier.citationREZENDE, F. M. P. de; FREITAS, M. P.; RAMALHO, T. C. Probing long-range spin-spin coupling constants in 2-halo-substituted cyclohexanones and cyclohexanethiones: the role of solvent and stereoelectronic effects. Magnetic Resonance in Chemistry, [S.l.], v. 56, n. 9, p. 810-816, Sept. 2018.pt_BR
dc.identifier.urihttps://onlinelibrary.wiley.com/doi/full/10.1002/mrc.4739pt_BR
dc.identifier.urihttp://repositorio.ufla.br/jspui/handle/1/34473-
dc.description.abstractEarlier studies with 2‐bromocyclohexanone demonstrated a measurable long‐range coupling constant (4JH2,H6) for the equatorial conformer, although 4JH2,H4 and 4JH4,H6 were not observed; as a consequence, it is inferred that the carbonyl group plays an important role particularly due to hyperconjugative interactions σC2H2→π*C═O and σC6H6→π*C═O. In the present study, NBO analysis and coupling constant calculations were performed to cyclohexanone and cyclohexanethione alpha substituted with F, Cl, and Br, aiming to evaluate the halogen effect and acceptor character of the π* orbital on the long‐range coupling pathway. The σC2H2→π*C1═Y and σC6H6→π*C1═Y (Y═O and S) hyperconjugative interactions for the equatorial conformer indeed contribute for the 4JH2,H6 transmission mechanism. Surprisingly, the 4JH2,H6 value is higher for the carbonyl compounds, although the interactions σC2H2→π*C═Y and σC6H6→π*C═Y are more efficient for the thiocarbonyl compounds. Accordingly, the Fermi contact (FC) contribution for the thiocarbonyl compounds decays deeper than in ketones, thus reducing more the 4JH2,H6 values. Moreover, both πC═S→σ*C─X and πC═S→σ*C─H interactions seem to be stronger in thiocarbonyl than in carbonylic compounds. The implicit solvent effect (DMSO and water) on the coupling constant values was negligible when compared with the gas phase. On the other hand, an explicit solvent effect was found and 4JH2,H6 for the thiocarbonyl compounds appeared to be more sensitive than for the cyclohexanones.pt_BR
dc.languageen_USpt_BR
dc.publisherWileypt_BR
dc.rightsrestrictAccesspt_BR
dc.sourceMagnetic Resonance in Chemistrypt_BR
dc.subjectFermi contactpt_BR
dc.subjectHalogenpt_BR
dc.subjectLong‐rangept_BR
dc.subjectSolventpt_BR
dc.titleProbing long-range spin-spin coupling constants in 2-halo-substituted cyclohexanones and cyclohexanethiones: the role of solvent and stereoelectronic effectspt_BR
dc.typeArtigopt_BR
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