Advertisement

Substituent effects on hyperfine coupling constants

  • E. Roduner
Part of the Lecture Notes in Chemistry book series (LNC, volume 49)

Abstract

27 monosubstituted benzenes ØX were measured either as pure liquids or in concentrated solutions. We use toluene as a model case to discuss the observed features and the assignment procedure. Three spectra are shown in Figure 5.1. At 3 kG three pairs of lines are observed (top). They correspond to radicals with coupling constants of A’μ = 153.8 MHz, 155.9 MHz, and 160.0 MHz, i.e. within 5% the same as the value of 161.7 MHz obtained for C6H6Mu in benzene. This is obviously typical for cyclohexadienyl type radicals. As was demonstrated for C6H6Mu one expects line splitting in a field of 1 kG when the second methylene hydrogen is H, and no splitting when it is D. This is seen for o-dideutero toluene (middle) where the absence of splitting of the two intense lines identifies the ortho Mu adduct. For p-deutero toluene (bottom) the smallest two lines are unsplit and therefore assigned to the para adduct. By default, the lines of intermediate intensity are assigned to the meta isomer. The ipso adduct is not observed. Because it would have no H in the methylene position it would not show splitting in a field of 1 kG.

Keywords

Substituent Effect Meta Position Hyperfine Coupling Constant Spin Density Distribution Spin Population 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • E. Roduner
    • 1
  1. 1.Physikalisch-Chemisches InstitutUniversität ZürichZürichSwitzerland

Personalised recommendations