Structural studies of N-(methoxysalicylidene)-fluroaniline, N-(methoxysalicylidene)-chloroaniline and N-(methoxysalicylidene)-bromoaniline derivatives

Twenty-seven N-(methoxysalicylidene)-haloaniline (halo = F, Cl or Br) compounds were synthesised. The crystal structures of all twenty-seven compounds have been determined at low temperature and are reported herein, along with a variable temperature neutron diffraction study on two of the compounds. New polymorphs were identified for two of the compounds along with a temperature induced phase transition for one of the other compounds. Visual observations on the thermochromism of the 27 compounds are also reported. The interplanar angle between the two aromatic rings and the intermolecular interactions in the structures are examined and linked to the visual observations on the thermochromism.