The rα stucture of 1,6,6aλ4 trithiapentalene and 1,6-dioxa-6aλ4-thiapentalene. A 1H-NMR study in the nematic phase including 13C- satellites in natural abundance

The ¹H-NMR spectra of 1,6,6aλ⁴-trithiapentalene and l,6-dioxa-6aλ⁴-thiapentalene in nematic phases have been recorded and analyzed. The ¹³C-¹H dipole-dipole couplings were obtained from the ¹³C satellites in natural abundance. Contributions from the harmonic vibrations to the dipole-dipole couplings have been calculated. The vibration-corrected dipole-dipole couplings yielded the r_α structure in accordance with a rigid C_ZV symmetry of the molecules. No evidence for a rapid valence tautonierization in the molecules was found.