DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines

All four isotropic contributions to the NMR fluorine-fluorine coupling constants (Fermi contact, FC, spin-dipolar, SD, paramagnetic spin-orbit, PSO, and diamagnetic spin-orbit, DSO) have been calculated for 2,6-difluoropyridine, 2,4,6-trifluoropyridine, perfluoropyridine, and 2-Br-3,4,5,6,7,8-hexafl...

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Detalles Bibliográficos
Autores principales:	Barone, Verónica, Peralta, Juan Ernesto, Contreras, Rubén Horacio
Publicado:	2002
Materias:	Density functional theory Finite perturbation theory scheme Fluorinated pyridines Spin-spin coupling constants Aromatic compounds Chemical bonds Fermi level Magnetization Molecular structure Perturbation techniques Probability density function Fluorine compounds
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v106_n23_p5607_Barone http://hdl.handle.net/20.500.12110/paper_10895639_v106_n23_p5607_Barone
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_10895639_v106_n23_p5607_Barone
record_format	dspace
spelling	paper:paper_10895639_v106_n23_p5607_Barone2023-06-08T16:06:17Z DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines Barone, Verónica Peralta, Juan Ernesto Contreras, Rubén Horacio Density functional theory Finite perturbation theory scheme Fluorinated pyridines Spin-spin coupling constants Aromatic compounds Chemical bonds Fermi level Magnetization Molecular structure Perturbation techniques Probability density function Fluorine compounds All four isotropic contributions to the NMR fluorine-fluorine coupling constants (Fermi contact, FC, spin-dipolar, SD, paramagnetic spin-orbit, PSO, and diamagnetic spin-orbit, DSO) have been calculated for 2,6-difluoropyridine, 2,4,6-trifluoropyridine, perfluoropyridine, and 2-Br-3,4,5,6,7,8-hexafluoroquinoline by means of density functional theory in combination with the rather modest 6-311G** basis set. Experimental values ranging from -20.3 to +45.8 Hz are semiquantitatively reproduced for three- to seven-bond couplings, suggesting that the different electronic effects responsible for the spin-spin interactions are adequately taken into account. In all cases, the relative importance of noncontact terms was examined. With few exceptions, the sum of the SD and PSO noncontact terms is larger than the FC contact contribution, even though in most cases the two noncontact values have opposite signs. The widespread assumption that the Fermi contact term dominates scalar spin-spin couplings in the case of light atoms would appear to be an oversimplification for JFF in polyfluorinated organic molecules. In addition, the CPU performance of the Fermi contact contribution calculated separately by the coupled-perturbed and the finite-perturbation methods was investigated showing the latter to be slightly more efficient. 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. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v106_n23_p5607_Barone http://hdl.handle.net/20.500.12110/paper_10895639_v106_n23_p5607_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	Density functional theory Finite perturbation theory scheme Fluorinated pyridines Spin-spin coupling constants Aromatic compounds Chemical bonds Fermi level Magnetization Molecular structure Perturbation techniques Probability density function Fluorine compounds
spellingShingle	Density functional theory Finite perturbation theory scheme Fluorinated pyridines Spin-spin coupling constants Aromatic compounds Chemical bonds Fermi level Magnetization Molecular structure Perturbation techniques Probability density function Fluorine compounds Barone, Verónica Peralta, Juan Ernesto Contreras, Rubén Horacio DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
topic_facet	Density functional theory Finite perturbation theory scheme Fluorinated pyridines Spin-spin coupling constants Aromatic compounds Chemical bonds Fermi level Magnetization Molecular structure Perturbation techniques Probability density function Fluorine compounds
description	All four isotropic contributions to the NMR fluorine-fluorine coupling constants (Fermi contact, FC, spin-dipolar, SD, paramagnetic spin-orbit, PSO, and diamagnetic spin-orbit, DSO) have been calculated for 2,6-difluoropyridine, 2,4,6-trifluoropyridine, perfluoropyridine, and 2-Br-3,4,5,6,7,8-hexafluoroquinoline by means of density functional theory in combination with the rather modest 6-311G** basis set. Experimental values ranging from -20.3 to +45.8 Hz are semiquantitatively reproduced for three- to seven-bond couplings, suggesting that the different electronic effects responsible for the spin-spin interactions are adequately taken into account. In all cases, the relative importance of noncontact terms was examined. With few exceptions, the sum of the SD and PSO noncontact terms is larger than the FC contact contribution, even though in most cases the two noncontact values have opposite signs. The widespread assumption that the Fermi contact term dominates scalar spin-spin couplings in the case of light atoms would appear to be an oversimplification for JFF in polyfluorinated organic molecules. In addition, the CPU performance of the Fermi contact contribution calculated separately by the coupled-perturbed and the finite-perturbation methods was investigated showing the latter to be slightly more efficient.
author	Barone, Verónica Peralta, Juan Ernesto Contreras, Rubén Horacio
author_facet	Barone, Verónica Peralta, Juan Ernesto Contreras, Rubén Horacio
author_sort	Barone, Verónica
title	DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
title_short	DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
title_full	DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
title_fullStr	DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
title_full_unstemmed	DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines
title_sort	dft calculation of nmr jff spin-spin coupling constants in fluorinated pyridines
publishDate	2002
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10895639_v106_n23_p5607_Barone http://hdl.handle.net/20.500.12110/paper_10895639_v106_n23_p5607_Barone
work_keys_str_mv	AT baroneveronica dftcalculationofnmrjffspinspincouplingconstantsinfluorinatedpyridines AT peraltajuanernesto dftcalculationofnmrjffspinspincouplingconstantsinfluorinatedpyridines AT contrerasrubenhoracio dftcalculationofnmrjffspinspincouplingconstantsinfluorinatedpyridines
_version_	1768544147083362304

DFT calculation of NMR JFF spin-spin coupling constants in fluorinated pyridines

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