13C chemical shift anisotorpy and the H–C–H bond angle of 13CH3 OH in a nematic liquid crystal solvent

Abstract

A pulsed FT NMR spectrometer is used to determine the anisotropy in the carbon‐13 chemical shift tensor and the H–C–H bond angle in methyl alcohol from studies in a nematic liquid crystal solvent. The H–C–H bond angle measured by proton magnetic resonance is 109 ° 20′ ± 4′. The signs of the coupling constants D13_CH, D_HH, and J13_CH and the ordering parameter S₃₃ are established to be all positive. The value of Δσ (¹³C) obtained from temperature studies of the nematic phase chemical shift is 69 ± 5 ppm. The anisotropy obtained from the nematic—isotropic phase chemical shift difference (at 77 °C) is 63 ± 6 ppm.