Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants

NMR J FH coupling constants transmitted through space are known to show several unusual peculiarities. The main three are (a) in many cases their experimental values are reported to be positive and in others, negative; (b) theoretical values show that in some cases they are substantially contributed...

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Autores principales: Contreras, R.H., Ducati, L.C., Tormena, C.F.
Formato: JOUR
Materias:
1hJ FH
Fermi hole
hydrogen bond
proximity effect
through-space transmission
<sup>1h</sup>J <sub>FH</sub>
Coupling constants
Critical analysis
Experimental values
Fermi contact
Fermi holes
Paramagnetic spins
Proximity effects
Qualitative analysis
Spin-spin coupling constants
Theoretical values
Paramagnetism
Hydrogen bonds
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00207608_v112_n19_p3158_Contreras
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00207608_v112_n19_p3158_Contreras
record_format dspace
spelling todo:paper_00207608_v112_n19_p3158_Contreras2023-10-03T14:18:43Z Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants Contreras, R.H. Ducati, L.C. Tormena, C.F. 1hJ FH Fermi hole hydrogen bond proximity effect through-space transmission <sup>1h</sup>J <sub>FH</sub> Coupling constants Critical analysis Experimental values Fermi contact Fermi holes Paramagnetic spins Proximity effects Qualitative analysis Spin-spin coupling constants Theoretical values Paramagnetism Hydrogen bonds NMR J FH coupling constants transmitted through space are known to show several unusual peculiarities. The main three are (a) in many cases their experimental values are reported to be positive and in others, negative; (b) theoretical values show that in some cases they are substantially contributed not only from the Fermi contact (FC) term but also from the paramagnetic spin orbit (PSO) term, and their respective signs could be either like or unlike; (c) in many cases it can hardly be expected that the corresponding F-H proximate interactions could be considered a "hydrogen bond," whereas in other cases it is evident that they are. For discussing points (a) and (b), characteristics of both the FC and PSO terms are discussed performing qualitative analyses based on their expressions given in terms of the polarization propagator formalism. Point (c) is discussed in terms of the well-known Bader's QTAIM method as well as recalling the known relationship between the transmissions of the Fermi hole and of the FC interaction of spin-spin coupling constants. © 2012 Wiley Periodicals, Inc. From QTAIM parameters, the presence of F-H hydrogen bonds for 1 and 2 were assessed. Considering that the sign of TSJ FH SSCC is negative for 1, whereas it is positive for 2, it is concluded that the TSJ FH SSCC sign is not indicative of the presence or absence of an F-H hydrogen bond. Instead, such different signs are indicative that their Fermi contact contributions are transmitted by exchange interactions. The actual sign is determined by the competition between the LP 1(F)/C-H and C-F/C-H overlaps, which yield different sign contributions. Copyright © 2012 Wiley Periodicals, Inc. 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_00207608_v112_n19_p3158_Contreras
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic 1hJ FH
Fermi hole
hydrogen bond
proximity effect
through-space transmission
<sup>1h</sup>J <sub>FH</sub>
Coupling constants
Critical analysis
Experimental values
Fermi contact
Fermi holes
Paramagnetic spins
Proximity effects
Qualitative analysis
Spin-spin coupling constants
Theoretical values
Paramagnetism
Hydrogen bonds
spellingShingle 1hJ FH
Fermi hole
hydrogen bond
proximity effect
through-space transmission
<sup>1h</sup>J <sub>FH</sub>
Coupling constants
Critical analysis
Experimental values
Fermi contact
Fermi holes
Paramagnetic spins
Proximity effects
Qualitative analysis
Spin-spin coupling constants
Theoretical values
Paramagnetism
Hydrogen bonds
Contreras, R.H.
Ducati, L.C.
Tormena, C.F.
Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
topic_facet 1hJ FH
Fermi hole
hydrogen bond
proximity effect
through-space transmission
<sup>1h</sup>J <sub>FH</sub>
Coupling constants
Critical analysis
Experimental values
Fermi contact
Fermi holes
Paramagnetic spins
Proximity effects
Qualitative analysis
Spin-spin coupling constants
Theoretical values
Paramagnetism
Hydrogen bonds
description NMR J FH coupling constants transmitted through space are known to show several unusual peculiarities. The main three are (a) in many cases their experimental values are reported to be positive and in others, negative; (b) theoretical values show that in some cases they are substantially contributed not only from the Fermi contact (FC) term but also from the paramagnetic spin orbit (PSO) term, and their respective signs could be either like or unlike; (c) in many cases it can hardly be expected that the corresponding F-H proximate interactions could be considered a "hydrogen bond," whereas in other cases it is evident that they are. For discussing points (a) and (b), characteristics of both the FC and PSO terms are discussed performing qualitative analyses based on their expressions given in terms of the polarization propagator formalism. Point (c) is discussed in terms of the well-known Bader's QTAIM method as well as recalling the known relationship between the transmissions of the Fermi hole and of the FC interaction of spin-spin coupling constants. © 2012 Wiley Periodicals, Inc. From QTAIM parameters, the presence of F-H hydrogen bonds for 1 and 2 were assessed. Considering that the sign of TSJ FH SSCC is negative for 1, whereas it is positive for 2, it is concluded that the TSJ FH SSCC sign is not indicative of the presence or absence of an F-H hydrogen bond. Instead, such different signs are indicative that their Fermi contact contributions are transmitted by exchange interactions. The actual sign is determined by the competition between the LP 1(F)/C-H and C-F/C-H overlaps, which yield different sign contributions. Copyright © 2012 Wiley Periodicals, Inc.
format JOUR
author Contreras, R.H.
Ducati, L.C.
Tormena, C.F.
author_facet Contreras, R.H.
Ducati, L.C.
Tormena, C.F.
author_sort Contreras, R.H.
title Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
title_short Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
title_full Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
title_fullStr Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
title_full_unstemmed Critical analysis of the through-space transmission of NMR J FH spin-spin coupling constants
title_sort critical analysis of the through-space transmission of nmr j fh spin-spin coupling constants
url http://hdl.handle.net/20.500.12110/paper_00207608_v112_n19_p3158_Contreras
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AT ducatilc criticalanalysisofthethroughspacetransmissionofnmrjfhspinspincouplingconstants
AT tormenacf criticalanalysisofthethroughspacetransmissionofnmrjfhspinspincouplingconstants
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