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Structure of p ‐tetrafluorobenzoquinone: interaction with nematic liquid crystals
Author(s) -
Arfaoui Youssef,
Haloui Ezzeddine
Publication year - 2000
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 - 10.1002/1097-458x(200008)38:8<639::aid-mrc689>3.0.co;2-p
Subject(s) - chemistry , liquid crystal , fluorine , dipole , ab initio , solvent , scalar (mathematics) , molecular orbital , crystallography , computational chemistry , molecule , analytical chemistry (journal) , chemical physics , organic chemistry , condensed matter physics , geometry , physics , mathematics
The orientation of p ‐tetrafluorobenzoquinone in four nematic liquid crystals with different aromaticities was determined by measuring the fluorine– fluorine and the fluorine– carbon scalar and dipolar couplings. Signs of the J (F,F) and the J (C,F) were determined without ambiguity. The experimental geometry was compared with those obtained by diffraction techniques and by ab initio molecular orbital calculations. Assuming a solvent– solute interaction potential based entirely on dispersion forces does not agree with experimental observations. The discrepancies are partly due to the formation of charge‐transfer molecular complexes. This latter contribution was confirmed by UV spectrophotometric measurements. Copyright © 2000 John Wiley & Sons, Ltd.