The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes

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In the title compounds, the relativistic spin-orbit corrections to 13C magnetic shielding constants are calculated as a quadratic response to the spin-orbit/Fermi contact (S-O/FC) perturbation. To carry out such calculations, the Gaussian 98 package of programs was properly modified. The FC operator...

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Detalles Bibliográficos
Autores principales:	Barone, Verónica, Contreras, Rubén Horacio
Publicado:	2003
Materias:	Chemical bonds Fermi level Halogen compounds Magnetic shielding Numerical methods Perturbation techniques Relativity Chemical shifts Fermi contact Finite perturbation Halobicyclopentanes Hydrocarbons
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00268976_v101_n9_p1297_Barone http://hdl.handle.net/20.500.12110/paper_00268976_v101_n9_p1297_Barone
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00268976_v101_n9_p1297_Barone
record_format	dspace
spelling	paper:paper_00268976_v101_n9_p1297_Barone2023-06-08T14:53:58Z The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes Barone, Verónica Contreras, Rubén Horacio Chemical bonds Fermi level Halogen compounds Magnetic shielding Numerical methods Perturbation techniques Relativity Chemical shifts Fermi contact Finite perturbation Halobicyclopentanes Hydrocarbons In the title compounds, the relativistic spin-orbit corrections to 13C magnetic shielding constants are calculated as a quadratic response to the spin-orbit/Fermi contact (S-O/FC) perturbation. To carry out such calculations, the Gaussian 98 package of programs was properly modified. The FC operator was introduced using the finite perturbation (FPT) approach, while the paramagnetic shielding operator was taken into account within the coupled perturbed Kohn-Sham approach, using a gauge single origin. In all cases the single origin was taken at the halogen nucleus. XH and CH3X (X = F, Cl, Br, I) compounds were taken as test cases to compare results obtained with this modified program to other values taken from the literature. Results obtained with different functionals are also compared. In 1-halo-bicyclo[1.1.1]pentanes, the calculated S-O/FC contributions to 13C magnetic shielding constants correspond to shielding effects for Cα and Cβ, and to deshielding effects for Cγ. Calculated S-O/FC contributions to the Cα magnetic shielding constants are larger than those calculated in CH3X. Such a result is in line with the high s character at the C atom of the C-X bond for the title compounds. © 2003 Taylor & Francis Group, LLC. Fil:Barone, V. 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. 2003 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00268976_v101_n9_p1297_Barone http://hdl.handle.net/20.500.12110/paper_00268976_v101_n9_p1297_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	Chemical bonds Fermi level Halogen compounds Magnetic shielding Numerical methods Perturbation techniques Relativity Chemical shifts Fermi contact Finite perturbation Halobicyclopentanes Hydrocarbons
spellingShingle	Chemical bonds Fermi level Halogen compounds Magnetic shielding Numerical methods Perturbation techniques Relativity Chemical shifts Fermi contact Finite perturbation Halobicyclopentanes Hydrocarbons Barone, Verónica Contreras, Rubén Horacio The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
topic_facet	Chemical bonds Fermi level Halogen compounds Magnetic shielding Numerical methods Perturbation techniques Relativity Chemical shifts Fermi contact Finite perturbation Halobicyclopentanes Hydrocarbons
description	In the title compounds, the relativistic spin-orbit corrections to 13C magnetic shielding constants are calculated as a quadratic response to the spin-orbit/Fermi contact (S-O/FC) perturbation. To carry out such calculations, the Gaussian 98 package of programs was properly modified. The FC operator was introduced using the finite perturbation (FPT) approach, while the paramagnetic shielding operator was taken into account within the coupled perturbed Kohn-Sham approach, using a gauge single origin. In all cases the single origin was taken at the halogen nucleus. XH and CH3X (X = F, Cl, Br, I) compounds were taken as test cases to compare results obtained with this modified program to other values taken from the literature. Results obtained with different functionals are also compared. In 1-halo-bicyclo[1.1.1]pentanes, the calculated S-O/FC contributions to 13C magnetic shielding constants correspond to shielding effects for Cα and Cβ, and to deshielding effects for Cγ. Calculated S-O/FC contributions to the Cα magnetic shielding constants are larger than those calculated in CH3X. Such a result is in line with the high s character at the C atom of the C-X bond for the title compounds. © 2003 Taylor & Francis Group, LLC.
author	Barone, Verónica Contreras, Rubén Horacio
author_facet	Barone, Verónica Contreras, Rubén Horacio
author_sort	Barone, Verónica
title	The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
title_short	The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
title_full	The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
title_fullStr	The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
title_full_unstemmed	The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
title_sort	spin—orbit/fermi contact effect on 13c substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes
publishDate	2003
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00268976_v101_n9_p1297_Barone http://hdl.handle.net/20.500.12110/paper_00268976_v101_n9_p1297_Barone
work_keys_str_mv	AT baroneveronica thespinorbitfermicontacteffecton13csubstituentchemicalshiftsin1halobicyclo111pentanes AT contrerasrubenhoracio thespinorbitfermicontacteffecton13csubstituentchemicalshiftsin1halobicyclo111pentanes AT baroneveronica spinorbitfermicontacteffecton13csubstituentchemicalshiftsin1halobicyclo111pentanes AT contrerasrubenhoracio spinorbitfermicontacteffecton13csubstituentchemicalshiftsin1halobicyclo111pentanes
_version_	1768542634052157440

The spin—orbit/Fermi contact effect on 13C substituent chemical shifts in 1-halo-bicyclo[1.1.1]pentanes

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