Synthesis and spectral studies of some rare earth metal complexes of a heterocyclic mesogenic Schiff-base

ABSTRACT

A heterocyclic liquid crystalline Schiff's base, N-(4′-(4″-hexyl-1H-1″,2″,3″-triazol))-4-dodecyloxysalicylaldimine (HL), and a series of lanthanide(III) complexes of the type [Ln(LH)₃(NO₃)₃] (Ln^III = La, Pr, Nd, Sm, Eu, Tb, and Dy) have been synthesized and characterized by elemental analyses, mass spectrometry, FTIR, NMR, and UV-Vis spectral techniques. All the complexes involve binding of HL (through phenolate oxygen in zwitter-ionic form) and bidentate chelation of nitrato groups. The ligand exhibits smectic-A (SmA) mesophase over a wide temperature range as evidenced by DSC and polarizing optical microscopic studies. Fluorescence studies show emissions of HL and Tb^III complex.

KEYWORDS:

• Mesogenic Schiff's base
• zwitter-ionic coordination
• Ln^III complexes

Funding

T. R. Rao, gratefully acknowledges the financial grant received from the Council of Scientific & Industrial Research, New Delhi [vide grant No. 01/2321/09/EMR/II] and M. Karunakar is grateful to the University Grants Commission (UGC), New Delhi, India, for providing financial assistance under research fellowship scheme for meritorious students.