Structural Study of Methyl Acrylate in a Nematic Liquid Crystal by 1 H NMR with 13 C Satellites

Abstract

The molecular structure and conformation of methyl acrylate have been determined by analyzing the 1H NMR spectrum with 13C satellites of the molecules dissolved in the liquid crystal ZLI 1132. In the structural analysis, direct coupling constants have been corrected for molecular vibrations and converted to those in the rα structure. The correlation between reorientational motion and internal rotation has been taken into account by using the mean external potential described in terms of bond interaction tensors. The potential for the internal rotation about the \(C{\kern 1pt} ---{\kern 1pt} C\) bond has been represented as V(Ψ) = (V1/2) (1 − cos Ψ) + (V2/2)(1 − cos 2Ψ), where Ψ is zero for the s-cis configuration, and the determined values of V1 and V2 are 2.7(1) and 8.4(13) kJ mol−1, respectively. The relative abundance of the s-cis conformer, 76(1)%, agrees with a gas-phase value, 67(11)%, determined by electron diffraction within experimental errors.