Rare Earth Metal Complexes of a Mesogenic Schiff-Base, N,N′-di-(4-decyloxysalicylidene)-1′, 4′-diaminobutane: Synthesis and Characterization

A mesogenic Schiff-base, N,N-di-(4-decyloxysalicylidene)-1,4-diaminobutane, (H2L) that exhibits smectic-B and nematic mesophases, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR techniques. H2L, upon condensation with hydrated lanthanide(III) nitrates yields Ln(III) complexes of the composition [Ln(2)(LH2)(3)(NO3)(4)](NO3)(2), where Ln(III) = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho. The Pr-III complex shows smectic-A and nematic phases. The IR and NMR spectral data imply a bidentate bonding of H2L in zwitterionic form (as LH2) to the Ln(III) ions through two phenolate oxygen atoms, rendering the overall geometry of the complexes possibly to distorted mono-capped octahedra.