Molecular polarisability. The conformations of acetanilide and certain of its N- and para-substituted derivatives

Abstract

The molar Kerr constants of acetanilide and certain N- and p-substituted acetanilides are analysed (using recently available amide group polarisability specifications) to indicate that (a) the preferred solute conformations of the molecules X·C₆H₄·NH·CO·CH₃(X = H, CH₃, Cl, or Br), examined in benzene or dioxan, are defined by a planar, cis arrangement of the group C_ar–N–CO and dihedral angles of 38°± 6°(standard deviation) between the amide group plane and that of the aromatic ring, and that (b) in N-methylacetanilide the CO is trans to the phenyl group.