NMR of partially oriented iodobenzene; A determination of the rα structure and of bond-contributions to the degree of order

The rα structure of iodobenzene corrected for correlated deformation has been derived from direct couplings measured in six different liquid crystal solvents. A comparison with other halogen substituted benzenes confirms a linear relation between the ipso angle and the substituent electronegativity. A study of the bond interaction parameters shows that the halogen substituent contributes significantly to the order parameters, particularly in liquid crystal solvents containing cyclohexane rings.