Probing long-range spin-spin coupling constants in 2-halo-substituted cyclohexanones and cyclohexanethiones: The role of solvent and stereoelectronic effects

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62690094%3A18450%2F18%3A50014750" target="_blank" >RIV/62690094:18450/18:50014750 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1002/mrc.4739" target="_blank" >http://dx.doi.org/10.1002/mrc.4739</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/mrc.4739" target="_blank" >10.1002/mrc.4739</a>

Result language

angličtina

Original language name

Probing long-range spin-spin coupling constants in 2-halo-substituted cyclohexanones and cyclohexanethiones: The role of solvent and stereoelectronic effects

Original language description

Earlier studies with 2-bromocyclohexanone demonstrated a measurable long-range coupling constant ((4)J(H2,H6)) for the equatorial conformer, although (4)J(H2,H4) and (4)J(H4,H6) were not observed; as a consequence, it is inferred that the carbonyl group plays an important role particularly due to hyperconjugative interactions sigma(C2H2)*(CO) and sigma(C6H6)*(CO.) 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 * orbital on the long-range coupling pathway. The sigma(C2H2)*(C1Y) and sigma(C6H6)*(C1Y) (YO and S) hyperconjugative interactions for the equatorial conformer indeed contribute for the (4)J(H2,H6) transmission mechanism(.) Surprisingly, the (4)J(H2,H6) value is higher for the carbonyl compounds, although the interactions sigma(C2H2)*(CY) and sigma(C6H6)*(CY) 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 (4)J(H2,H6) values. Moreover, both (CS)sigma*(CX) and (CS)sigma*(CH) 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 (4)J(H2,H6) for the thiocarbonyl compounds appeared to be more sensitive than for the cyclohexanones.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10401 - Organic chemistry

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Magnetic resonance in chemistry

ISSN

0749-1581

e-ISSN

—

Volume of the periodical

56

Issue of the periodical within the volume

9

Country of publishing house

US - UNITED STATES

Number of pages

7

Pages from-to

810-816

UT code for WoS article

000442497600004

EID of the result in the Scopus database

2-s2.0-85047838402