19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes

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In the process of studying the chemistry of perfluoro[2.2]paracyclophanes (PFPCs), a novel class of compounds, it became necessary to identify some disubstituted products. To achieve this goal, we characterize in this work some monosubstituted PFPCs, identifying their 19F-19F coupling patterns, and...

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Autor principal: Contreras, Rubén Horacio
Publicado: 2011
Materias:
19F chemical shifts
19F-19F couplings
conformation
FCCP-CMO
Fermi hole
NMR
paracyclophane
perfluoro[2.2]paracyclophane
through-space
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v49_n3_p93_Ghiviriga
http://hdl.handle.net/20.500.12110/paper_07491581_v49_n3_p93_Ghiviriga
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_07491581_v49_n3_p93_Ghiviriga
record_format dspace
spelling paper:paper_07491581_v49_n3_p93_Ghiviriga2023-06-08T15:45:38Z 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes Contreras, Rubén Horacio 19F chemical shifts 19F-19F couplings conformation FCCP-CMO Fermi hole NMR paracyclophane perfluoro[2.2]paracyclophane through-space In the process of studying the chemistry of perfluoro[2.2]paracyclophanes (PFPCs), a novel class of compounds, it became necessary to identify some disubstituted products. To achieve this goal, we characterize in this work some monosubstituted PFPCs, identifying their 19F-19F coupling patterns, and establishing a methodology for the assignment of their 19F chemical shifts. The pattern of coupling constants indicates a skewed geometry in which the upper deck moves towards or away from the substituent, depending on the substituent electron-donor character and size. Quantum chemical calculations, performed at the HF/6-311 + G(d,p)//B3LYP/EPR-III level of theory, confirmed the conformations inferred from coupling constants and reproduced well the values of the couplings. Transmission mechanisms for the FC term of four-and five-bond 19F-19F couplings are discussed in detail. Understanding the conformational preferences of PFPCs and how they are reflected by the coupling constants facilitates the assignment of 19F chemical shifts in monosubstituted PFPCs and the identification of the disubstituted products. Copyright © 2011 John Wiley & Sons, Ltd. Fil:Contreras, R.H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v49_n3_p93_Ghiviriga http://hdl.handle.net/20.500.12110/paper_07491581_v49_n3_p93_Ghiviriga
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic 19F chemical shifts
19F-19F couplings
conformation
FCCP-CMO
Fermi hole
NMR
paracyclophane
perfluoro[2.2]paracyclophane
through-space
spellingShingle 19F chemical shifts
19F-19F couplings
conformation
FCCP-CMO
Fermi hole
NMR
paracyclophane
perfluoro[2.2]paracyclophane
through-space
Contreras, Rubén Horacio
19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
topic_facet 19F chemical shifts
19F-19F couplings
conformation
FCCP-CMO
Fermi hole
NMR
paracyclophane
perfluoro[2.2]paracyclophane
through-space
description In the process of studying the chemistry of perfluoro[2.2]paracyclophanes (PFPCs), a novel class of compounds, it became necessary to identify some disubstituted products. To achieve this goal, we characterize in this work some monosubstituted PFPCs, identifying their 19F-19F coupling patterns, and establishing a methodology for the assignment of their 19F chemical shifts. The pattern of coupling constants indicates a skewed geometry in which the upper deck moves towards or away from the substituent, depending on the substituent electron-donor character and size. Quantum chemical calculations, performed at the HF/6-311 + G(d,p)//B3LYP/EPR-III level of theory, confirmed the conformations inferred from coupling constants and reproduced well the values of the couplings. Transmission mechanisms for the FC term of four-and five-bond 19F-19F couplings are discussed in detail. Understanding the conformational preferences of PFPCs and how they are reflected by the coupling constants facilitates the assignment of 19F chemical shifts in monosubstituted PFPCs and the identification of the disubstituted products. Copyright © 2011 John Wiley & Sons, Ltd.
author Contreras, Rubén Horacio
author_facet Contreras, Rubén Horacio
author_sort Contreras, Rubén Horacio
title 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
title_short 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
title_full 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
title_fullStr 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
title_full_unstemmed 19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
title_sort 19f chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes
publishDate 2011
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07491581_v49_n3_p93_Ghiviriga
http://hdl.handle.net/20.500.12110/paper_07491581_v49_n3_p93_Ghiviriga
work_keys_str_mv AT contrerasrubenhoracio 19fchemicalshiftscouplingconstantsandconformationalpreferencesinmonosubstitutedperfluoroparacyclophanes
_version_ 1768543281582440448

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