title: 1hJFH coupling in 2-fluorophenol revisited: is intramolecular hydrogen bond responsible for this long-range coupling?
abstract: 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.
authors.affiliation: Chemistry Institute, University of Campinas, Campinas, SP, Brazil.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Cormanich
authors.forename: Marilua A
authors.initials: MA
authors.lastname: Moreira
authors.forename: Matheus P
authors.initials: MP
authors.lastname: Freitas
authors.forename: Teodorico C
authors.initials: TC
authors.lastname: Ramalho
authors.forename: Cléber P A
authors.initials: CP
authors.lastname: Anconi
authors.forename: Roberto
authors.initials: R
authors.lastname: Rittner
authors.forename: Rubén H
authors.initials: RH
authors.lastname: Contreras
authors.forename: Cláudio F
authors.initials: CF
authors.lastname: Tormena
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002627:Chemistry, Physical; D003510:Cyclohexanes / Q000737:chemistry; D004583:Electrons; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D010636:Phenols / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D000097:Acetonitriles; D003510:Cyclohexanes; D010636:Phenols; C506365:Cyclohexane; C487839:2-fluorophenol; C032159:acetonitrile