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1h J FH coupling in 2‐fluorophenol revisited: Is intramolecular hydrogen bond responsible for this long‐range coupling?
Author(s) -
Cormanich Rodrigo A.,
Moreira Marilua A.,
Freitas Matheus P.,
Ramalho Teodorico C.,
Anconi Cléber P. A.,
Rittner Roberto,
Contreras Rubén H.,
Tormena Cláudio F.
Publication year - 2011
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2838
Subject(s) - chemistry , intramolecular force , hydrogen bond , fermi contact interaction , atomic orbital , coupling (piping) , molecule , chemical physics , computational chemistry , atomic physics , stereochemistry , quantum mechanics , physics , organic chemistry , mechanical engineering , hyperfine structure , engineering , electron
The present study shows that a hydrogen bond between the OH group and the fluorine atom is not involved in the 1h J FH spin–spin coupling transmission either for 4‐bromo‐2‐fluorophenol or 2‐fluorophenol. In fact, according to a quantum theory of atoms in molecules analysis, no bond critical point is found between O‐H and F moieties. The nature of the transmission mechanism of the Fermi contact term of the 1h J FH spin–spin coupling is studied by analyzing canonical molecular orbitals (see J. Phys. Chem. A 2010, 114, 1044), and it is observed that virtual orbitals play only a quite minor role in its transmission. This is typical of a Fermi contact term transmitted mainly through exchange interactions owing to the overlap of proximate electronic clouds; therefore, it is suggested to identify them as nTS J FH coupling where n stands for the number of formal bonds separating the coupling nuclei. In the cases studied in this work is n = 4. Results presented in this work could provide an interesting rationalization for different experimental signs known in the current literature for proximate J FH couplings. Copyright © 2011 John Wiley & Sons, Ltd.