The rα‐structure of partially oriented 1,2,3,5‐tetrachlorobenzene determined from its 1H NMR spectra with natural‐abundance 13C‐satellites. A Demonstration of the Combined Use of Spectra Obtained from Molecules Dissolved in Several Different Liquid Crystals as Solvents for Spin Systems not having enough Dipolar Coupling Constants to Determine the Molecular Structure

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Abstract
It is demonstrated that in a case where neither the proton nor the natural‐abundance 13C‐satellite spectra of a partially oriented molecule carry enough structural information, one can determine the entire molecular geometry by the combined use of several liquid crystals as solvents. As an example, the spectrum of 1,2,3,5‐tetrachlorobenzene is analysed and the rα‐structure is computed after vibration corrections of the dipolar coupling constants obtained in two different liquid crystals. The carbon‐hydrogen, carbon‐carbon internuclear distance ratios as well as bond lengths and angles are determined. The solvent effect of the two different nematic phases on the molecular structure is investigated and found to be negligible. Indirect proton‐proton and proton‐carbon couplings, as well as one‐bond and two‐bond 13C isotope effects on the proton chemical shifts, are measured in an isotropic solvent.