Iron(III) metallomesogen of [N 2 O 2 ] donor Schiff base ligand containing 4-substituted alkoxy chains

Two new square pyramidal iron(III)-complexes of ‘salen’-type Schiff base ligands containing 4-substituted long alkoxy arms on the aromatic rings, [Fe(4-C 16 H 33 O) 2 salcn)]Cl and [Fe(4-C 16 H 33 O) 2 salophen)]Cl {salcn = N,Nʹ-cyclohexanebis(salicylideneiminato) and salophen = N,Nʹ-phenylenebis(salicylideneiminato)}, have been successfully synthesised, and their mesomorphic property investigated. The ligands and complexes were characterised by elemental analyses, UV–Vis, FT-IR, ESI–MS, 1 H and 13 C NMR (for ligands only).

The phase behaviour of the iron(III) complexes were ascertained by differential scanning calorimetry, polarising optical microscopy and variable temperature PXRD study. Ligands are non-mesomorphic, however, mesomorphism got induced upon complexation with the iron(III) centre. X-ray diffraction study revealed a layer-like arrangement of the five coordinated mesomorphic iron(III) complexes.