The barrier to internal rotation in benzyl fluoride investigated using the N.M.R. spectra of samples dissolved in liquid crystalline solvents
- 10 June 1989
- journal article
- research article
- Published by Taylor & Francis in Molecular Physics
- Vol. 67 (2) , 239-248
- https://doi.org/10.1080/00268978900101051
Abstract
The proton and fluorine spectra of samples of benzyl fluoride dissolved in two nematic solvents (ZLI 1132 and I52) have been analysed to yield sets of dipolar couplings [Dtilde]ij between the interacting nuclei. These were compared with values calculated by a theoretical model which allows for the dependence of orientational order on the angle that the C-F bond makes with the plane of the phenyl ring. The observed and calculated [Dtilde]ij are in excellent agreement, and the potential for rotation about the C-CH2F bond is found to have a minimum when the C-F bond is in the plane at 90° to the phenyl ring, but the barrier height changes from 0·3 ± 0·02 kJ mol-1 in I52 to 1·5 ± 0·08 kJ mol-1 for ZLI 1132 as solvent.Keywords
This publication has 14 references indexed in Scilit:
- The potential function for rotation about the phenyl-C bond in 3,5-dibromoethylbenzeneMolecular Physics, 1988
- An investigation of the potential governing rotation about the O—CH2bond in 4-chloroethoxybenzene by comparing observed and calculated dipolar couplings obtained for a sample dissolved in a nematic solventJournal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 1988
- The benzylic anomeric effect. Internal rotational potentials of ArCH2X compounds (X = F, Cl, SH, SCH3, S(O)CH3, SO2CH3)Canadian Journal of Chemistry, 1987
- Solvent-induced conformational changes in benzyl fluoride. Long-range C,F; H,H; H,F spin–spin couplingsCanadian Journal of Chemistry, 1985
- NMR spin-echo spectra of molecules containing four nuclei with aa′bb′ symmetry in liquid-crystalline samplesJournal of Magnetic Resonance (1969), 1983
- A theory of orientational ordering in uniaxial liquid crystals composed of molecules with alkyl chainsProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1982
- Nuclear spin relaxation in benzyl fluoride. I. 2H relaxation for internal rotational barrier determination and 1H and 19F intra- and intermolecular relaxation in pure benzyl fluorideJournal of Magnetic Resonance (1969), 1981
- Chemically induced dynamic polarisation of19F nuclei in the dimerisation of α-fluorobenzyl radicalsJournal of the Chemical Society, Perkin Transactions 2, 1979
- Spin—spin coupling and the conformational states of peptide systemsProgress in Nuclear Magnetic Resonance Spectroscopy, 1976
- Preferential conformation of the carbon-fluorine bond and electronic interactions in substituted benzyl fluoridesJournal of Fluorine Chemistry, 1976