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Three‐centre hydrogen bonding in the complexes of syn ‐2,4‐difluoroadamantane with 4‐fluorophenol and hydrogen fluoride
Author(s) -
Adcock William,
Graton Jérôme,
Laurence Christian,
Luçon Maryvonne,
Trout Neil
Publication year - 2005
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.813
Subject(s) - chemistry , hydrogen bond , low barrier hydrogen bond , hydrogen , molecule , acceptor , density functional theory , ab initio , crystallography , hydrogen fluoride , gibbs free energy , fluorine , bond energy , computational chemistry , bond order , bond length , inorganic chemistry , organic chemistry , thermodynamics , physics , condensed matter physics
Hydrogen bond enthalpies for the interaction of 4‐fluorophenol with syn ‐2,4‐difluoroadamantane ( 5 ) and, for comparison, 2‐fluoroadamantane ( 6 ) and 1,3‐difluoroadamantane ( 7 ) have been determined by Fourier transform infrared spectrometry. Among a series of seven fluoroalkanes ( 1–7 ) it is found that syn ‐2,4‐difluoroadamantane is the best hydrogen bond acceptor. This high hydrogen bond acceptor strength is explained, using electrostatic and ‘atoms in molecules’ properties and from density functional theory and ab initio calculations on hydrogen fluoride complexes, by the formation of an F·H·F three‐centre hydrogen bond. In this system, the three‐centre hydrogen bonding is energetically (mainly on the Gibbs energy scale) superior to the two‐centre hydrogen bonding. Copyright © 2004 John Wiley & Sons, Ltd.