Isotope effects on the degree of order and the deuterium quadrupole coupling constants, as measured by N.M.R. of oriented benzene-d₁, 1,4-benzene-d₂ and 1,3,5-benzene-d₃

Abstract

Proton and deuteron magnetic resonance spectra of benzene-d ₁, 1,4-benzene-d ₂ and 1,3,5-benzene-d ₃, oriented in various liquid crystal solvents have been analysed. Isotope effects on the degree of order have been measured. The ratios of S-values in the benzene plane are found to be S_xx/S_zz =1·0201 ± 0·0009 in benzene-d ₁ and 1·0389 ± 0·0004 in 1,4-benzene-d ₂ with the deuterons substituted on the z-axis. Deuteron quadrupole coupling constants of 190·4 ± 1·2 kHz and 192·4 ± 1·2 kHz have been obtained for 1,4-benzene-d ₂ and 1,3,5-benzene-d ₃.