Conformational effects on 13C NMR parameters in alkyl formates

The 13C NMR spectra of a series of alkyl formates which show the coexistence of s-cis and s-trans rotamers at room temperature were measured at 125 MHz. 13C chemical shifts and 1J(CH) couplings are compared for both types of rotamers. Their differences are rationalized in terms of different intramol...

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Detalles Bibliográficos
Publicado: 1998
Materias:
13C NMR
17O NMR
Ab initio LORG study
Alkyl formates
Conformational effects
NMR
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v36_n5_p336_DeKowalewski
http://hdl.handle.net/20.500.12110/paper_07491581_v36_n5_p336_DeKowalewski
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_07491581_v36_n5_p336_DeKowalewski
record_format dspace
spelling paper:paper_07491581_v36_n5_p336_DeKowalewski2023-06-08T15:45:32Z Conformational effects on 13C NMR parameters in alkyl formates 13C NMR 17O NMR Ab initio LORG study Alkyl formates Conformational effects NMR The 13C NMR spectra of a series of alkyl formates which show the coexistence of s-cis and s-trans rotamers at room temperature were measured at 125 MHz. 13C chemical shifts and 1J(CH) couplings are compared for both types of rotamers. Their differences are rationalized in terms of different intramolecular interactions. The 17O NMR spectra of these compounds could be observed only for the most abundant rotamer, which in all cases was identified as the s-cis rotamer. In the three members of this series with the shortest alkyl chains, a 2J(17O,1H) coupling constant of ca. 40 Hz was observed. In ethyl formate, 13C magnetic shielding constants were calculated using the LORG approach with ab initio optimized geometries in both types of rotamers for the carbon atom β to the dicoordinated oxygen atom. A comparison between the calculated and experimental values yields support for the rationalizations quoted above. © 1998 John Wiley & Sons, Ltd. 1998 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v36_n5_p336_DeKowalewski http://hdl.handle.net/20.500.12110/paper_07491581_v36_n5_p336_DeKowalewski
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic 13C NMR
17O NMR
Ab initio LORG study
Alkyl formates
Conformational effects
NMR
spellingShingle 13C NMR
17O NMR
Ab initio LORG study
Alkyl formates
Conformational effects
NMR
Conformational effects on 13C NMR parameters in alkyl formates
topic_facet 13C NMR
17O NMR
Ab initio LORG study
Alkyl formates
Conformational effects
NMR
description The 13C NMR spectra of a series of alkyl formates which show the coexistence of s-cis and s-trans rotamers at room temperature were measured at 125 MHz. 13C chemical shifts and 1J(CH) couplings are compared for both types of rotamers. Their differences are rationalized in terms of different intramolecular interactions. The 17O NMR spectra of these compounds could be observed only for the most abundant rotamer, which in all cases was identified as the s-cis rotamer. In the three members of this series with the shortest alkyl chains, a 2J(17O,1H) coupling constant of ca. 40 Hz was observed. In ethyl formate, 13C magnetic shielding constants were calculated using the LORG approach with ab initio optimized geometries in both types of rotamers for the carbon atom β to the dicoordinated oxygen atom. A comparison between the calculated and experimental values yields support for the rationalizations quoted above. © 1998 John Wiley & Sons, Ltd.
title Conformational effects on 13C NMR parameters in alkyl formates
title_short Conformational effects on 13C NMR parameters in alkyl formates
title_full Conformational effects on 13C NMR parameters in alkyl formates
title_fullStr Conformational effects on 13C NMR parameters in alkyl formates
title_full_unstemmed Conformational effects on 13C NMR parameters in alkyl formates
title_sort conformational effects on 13c nmr parameters in alkyl formates
publishDate 1998
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v36_n5_p336_DeKowalewski
http://hdl.handle.net/20.500.12110/paper_07491581_v36_n5_p336_DeKowalewski
_version_ 1768542892700205056

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