Multiple-quantum NMR spectroscopy of molecules aligned in liquid-crystalline solvents

https://doi.org/10.1016/0022-2364(92)90027-5Get rights and content

Abstract

Multiple-quantum proton NMR spectra of 3-chloroiodobenzene and 1-bromonaphthalene aligned as dilute solutions in liquid-crystalline solvents were obtained indirectly as projections from two-dimensional experiments. Spectra were acquired using a phase-cycled pulse sequence which nonselectively excited multiple-quantum coherence in the spin system but filtered the observed signal to give multiple-quantum spectra of the desired order. For the seven-proton spin system of 1-bromonaphthalene aligned in liquid-crystalline solution, the five- and six-quantum spectra were analyzed to give all interproton dipolar coupling constants (Dij) and these were used to establish the geometry and the average orientation of the proton skeleton of the molecule.

References (21)

  • S Sinton
  • B.K John et al.

    J. Magn. Reson.

    (1984)
    P Meakin et al.

    J. Magn. Reson.

    (1975)
    P Meakin et al.

    J. Magn. Reson.

    (1974)
    P Meakin et al.

    J. Magn. Reson.

    (1973)
    A.D Bain

    J. Magn. Reson.

    (1980)
    A.D Bain et al.

    Can. J Chem.

    (1981)
  • P Diehl et al.
  • R.G Jones
  • M Hamermesh

    Group Theory and Its Application to Physical Problems

    (1959)
  • F.A Cotton

    Chemical Applications of Group Theory

    (1971)
  • G Drobny et al.
  • J.W Emsley et al.

    J. Chem. Soc. B

    (1970)
  • P Diehl et al.

    Mol. Phys.

    (1971)
  • P Diehl et al.

    Org. Magn. Reson.

    (1974)
There are more references available in the full text version of this article.

Cited by (20)

  • Multiple Quantum NMR of Partially Aligned Molecules

    2006, Annual Reports on NMR Spectroscopy
    Citation Excerpt :

    The simplest approach to selective detection of MQ spectra involves phase-cycling in the basic 3–pulse sequence (in Fig. 2) to allow selection of the spectrum of a particular order of coherence. In any spin system, order selective detection of the spectrum of order N is achieved by coadding 4N FIDs at each value of t1 with the phase of the first two pulses incremented from 2π/4N to 2π in steps of 2π/4N with the receiver phase incremented by π/2 at each step (Fig. 6).30–33 Fig. 7 provides an example of the selective detection of the 3–quantum spectrum of the 4–spin system of 3–chloroiodbenzene (2) aligned in nematic liquid crystalline solution.

  • Novel method of estimating proton-proton dipolar couplings to aid the analyses of NMR spectra of oriented molecules using two-dimensional inverse experiment

    2001, Chemical Physics Letters
    Citation Excerpt :

    However, one of the major problems of analysis, namely, initial estimation of proton–proton dipolar couplings still persists. Several techniques have been reported in the literature either to simplify the complex spectra or to aid their analysis [9–14]. None of these techniques provide direct estimation of the proton–proton dipolar couplings from the oriented spectra.

View all citing articles on Scopus
View full text