Synthesis and Characterization of Novel Metallomesogens: La(Iii), Pr(Iii) and Nd(Iii) Complexes of N-(2-Hydroxy-4-N-Alkoxy-Benzaldehydeimino)-2-Benzamidoethanamide

A novel series of liquid crystalline compounds, N-(2-hydroxy-4-n-alkoxy-benzaldehydeimino)-2-benzamidoethanamide (habbe) (alkyl = octyl, nonyl and decyl), derived from (N-benzoyl)glycylhydrazide, have been synthesized and characterized. Trivalent rare earth metal complexes of the type [Ln(habbe)2Cl2)Cl·2H2O] (where Ln = La(III), Pr(III) and Nd(III)) have been synthesized and characterized by elemental analyses, IR and NMR (1H and 13C) spectral studies. The coordinating behaviour of the liquid crystalline habbe series towards the lanthanide metal ions were studied by IR and NMR spectral techniques. Further, the preliminary studies of thermal microscopy (TM) (polarizing microscope with a hot stage) and differential scanning calorimetry (DSC) confirm the presence of liquid crystalline phases in the present series of habbe derivatives and their complexes. IR and NMR spectral data strongly suggest a neutral tridentate behaviour of the mesogen ligands in the complexes.