Molecular Interactions in Chiral Nematic Liquid Crystals and Enantiotopic Discrimination through the NMR Spectra of Achiral Molecules I: Rigid Solutes

TL;DR

This paper presents a molecular theory explaining how NMR spectra can distinguish enantiotopic sites in achiral molecules dissolved in chiral nematic liquid crystals, validated by experimental data.

Contribution

It introduces a comprehensive potential of mean torque including symmetric and antisymmetric tensor contributions for enantiotopic discrimination in NMR.

Findings

The theory accurately predicts enantiotopic discrimination for rigid acenaphthene.

It also successfully describes moderate flexibility effects in ethanol.

Excellent quantitative agreement with experimental NMR data.

Abstract

We have developed a molecular theory for the enantiotopic discrimination in prochiral solutes dissolved in chiral nematic solvents by means of NMR spectroscopy. The leading rank tensor contributions to the proposed potential of mean torque include symmetric as well as antisymmetric terms with respect to spatial inversion, these lead to a consistent determination of all the prochiral solute symmetries for which enantiotopes are distinguishable by NMR and also to excellent quantitative agreement when tested against the available experimental data for the rigid solute acenaphthene and for the moderately flexible ethanol.