The rα-structure and the 1H and 199Hg shielding anisotropies of dimethylmercury as determined in nematic and smectic liquid crystal solvents

The complete r_α-structure of dimethylmercury in the nematic ZLI 1167 liquid crystal was determined. This study confirms the earlier results, indicating that the structure is practically independent of the liquid crystal solvent, although some minor deviations exist. The Hg? C distance was found to be 207.97±0.05 pm, when the vibration corrections in the dipole-dipole coupling constants were taken into account. This is rather similar to the distances obtained with other spectroscopic methods. The anisotropies of the ¹H and ¹⁹⁹Hg chemical shifts were obtained by using a smectic liquid crystal and recording the corresponding spectra, the optical axis being parallel with or perpendicular to the external field direction. The experimental ratio-2.007±0.017 of the D∥ (HgH) and D? (HgH) coupling constants proves that the indirect contributions in these coupling constants are negligible. Shielding anisotropies of 3.70±0.3 ppm and 7325±55 ppm for ¹H and ¹⁹⁹Hg, respectively, were obtained.