Lanthanide complexes of Schiff base ligands containing three aromatic rings: synthesis and thermal behaviour

The synthesis and thermal behaviour of liquid-crystalline lanthanide complexes with Schiff base ligands are described. The stoichiometry of the rare-earth complexes is [Ln(LH)L2(NO3)], where Ln=La(III), Nd(III), Pr(III), Eu(III), Gd(III), Ho(III), Er(III), and LH is the Schiff base 4-({3-Hydroxy-4-[(octadecylimino)methyl]phenoxy}carbonyl)phenyl 4-(hexyloxy)benzoate. The ligand displays a smectic C (SmC) and a nematic (N) phase. In the metal complexes, the nematic phase is suppressed and only a smectic C phase is present.