Nematic phase nuclear magnetic resonance investigation of rotational isomerism. Part 6. The conformation of thiophenol in solution

Abstract

The 100 MHz n.m.r. spectra of thiophenol and 4-chlorothiophenol oriented in a liquid crystalline solvent were obtained and interpreted. Analysis of the direct dipolar couplings shows that in both molecules a planar conformation would require a [graphic omitted] angle distorted by 7—10° with respect to the known values of thiols. On the other hand a non-planar conformation with the CSH plane twisted by 26 ± 3° with respect to the phenyl ring agrees with the structural parameters of thiols and with the experimental dipolar couplings. It has been also observed that the off-diagonal element of the ordering matrix S_xy is negligible, thus suggesting that rotation of the SH group occurs faster than molecular reorientation.