Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods

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Substituent effects for 2J(F,F) couplings in aliphatic and olefinic CF2 moieties and 3J(F,F) couplings in fluorinated derivatives of ethylene were studied using both high level ab initio and DFT/B3LYP calculations. Where possible, J variations have been compared with experimental values. In general,...

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Autores principales: Barone, V., Provasi, P.F., Peralta, J.E., Snyder, J.P., Sauer, S.P.A., Contreras, R.H.
Formato: JOUR
Materias:
Moieties
Derivatives
Ethylene
Fluorine compounds
Nuclear magnetic resonance spectroscopy
Perturbation techniques
Probability density function
Hydrogen bonds
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_10895639_v107_n23_p4748_Barone
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_10895639_v107_n23_p4748_Barone
record_format dspace
spelling todo:paper_10895639_v107_n23_p4748_Barone2023-10-03T16:04:31Z Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods Barone, V. Provasi, P.F. Peralta, J.E. Snyder, J.P. Sauer, S.P.A. Contreras, R.H. Moieties Derivatives Ethylene Fluorine compounds Nuclear magnetic resonance spectroscopy Perturbation techniques Probability density function Hydrogen bonds Substituent effects for 2J(F,F) couplings in aliphatic and olefinic CF2 moieties and 3J(F,F) couplings in fluorinated derivatives of ethylene were studied using both high level ab initio and DFT/B3LYP calculations. Where possible, J variations have been compared with experimental values. In general, the SOPPA (second-order polarization propagator approximation) methodology matches absolute experimental values reasonably well, whereas the DFT/B3LYP approach performs poorly in describing 2J(F,F) couplings. Fortunately, substituent effects for DFT J couplings are notably better reproduced. For a vinyl CF2 moiety, the accurate prediction of 2J(F,F) couplings is a challenging task even for high level ab initio methods such as SOPPA and SOPPA(CCSD) (second-order polarization propagator approximation with coupled cluster singles and doubles amplitudes). Aliphatic 2J(F,F) couplings are very sensitive to the electronegativity of substituents placed a to the CF2 group. The latter J perturbations are dominated largely by the noncontact PSO and SD Ramsey contributions, whereas the influence of the FC term is rather small. Substituent effects on 2J(F,F) and 3J(F,F) couplings in fluorinated derivatives of ethylene are also dominated by non-Fermi contributions. Because DFT/B3LYP strongly underestimates the FC contribution, but generally assesses the non-Fermi terms similar to SOPPA, the latter accounts for DFT's ability to predict substituent effects reasonably well. Fil:Barone, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Peralta, J.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Contreras, R.H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_10895639_v107_n23_p4748_Barone
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Moieties
Derivatives
Ethylene
Fluorine compounds
Nuclear magnetic resonance spectroscopy
Perturbation techniques
Probability density function
Hydrogen bonds
spellingShingle Moieties
Derivatives
Ethylene
Fluorine compounds
Nuclear magnetic resonance spectroscopy
Perturbation techniques
Probability density function
Hydrogen bonds
Barone, V.
Provasi, P.F.
Peralta, J.E.
Snyder, J.P.
Sauer, S.P.A.
Contreras, R.H.
Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
topic_facet Moieties
Derivatives
Ethylene
Fluorine compounds
Nuclear magnetic resonance spectroscopy
Perturbation techniques
Probability density function
Hydrogen bonds
description Substituent effects for 2J(F,F) couplings in aliphatic and olefinic CF2 moieties and 3J(F,F) couplings in fluorinated derivatives of ethylene were studied using both high level ab initio and DFT/B3LYP calculations. Where possible, J variations have been compared with experimental values. In general, the SOPPA (second-order polarization propagator approximation) methodology matches absolute experimental values reasonably well, whereas the DFT/B3LYP approach performs poorly in describing 2J(F,F) couplings. Fortunately, substituent effects for DFT J couplings are notably better reproduced. For a vinyl CF2 moiety, the accurate prediction of 2J(F,F) couplings is a challenging task even for high level ab initio methods such as SOPPA and SOPPA(CCSD) (second-order polarization propagator approximation with coupled cluster singles and doubles amplitudes). Aliphatic 2J(F,F) couplings are very sensitive to the electronegativity of substituents placed a to the CF2 group. The latter J perturbations are dominated largely by the noncontact PSO and SD Ramsey contributions, whereas the influence of the FC term is rather small. Substituent effects on 2J(F,F) and 3J(F,F) couplings in fluorinated derivatives of ethylene are also dominated by non-Fermi contributions. Because DFT/B3LYP strongly underestimates the FC contribution, but generally assesses the non-Fermi terms similar to SOPPA, the latter accounts for DFT's ability to predict substituent effects reasonably well.
format JOUR
author Barone, V.
Provasi, P.F.
Peralta, J.E.
Snyder, J.P.
Sauer, S.P.A.
Contreras, R.H.
author_facet Barone, V.
Provasi, P.F.
Peralta, J.E.
Snyder, J.P.
Sauer, S.P.A.
Contreras, R.H.
author_sort Barone, V.
title Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
title_short Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
title_full Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
title_fullStr Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
title_full_unstemmed Substituent effects on scalar 2J(19F,19F) and 3J(19F,19F) NMR couplings: A comparison of SOPPA and DFT methods
title_sort substituent effects on scalar 2j(19f,19f) and 3j(19f,19f) nmr couplings: a comparison of soppa and dft methods
url http://hdl.handle.net/20.500.12110/paper_10895639_v107_n23_p4748_Barone
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