Synthesis and Characterization of Mixed Ligand Complexes of Lanthanides(III)

Abstract

Mixed ligand complexes of rare earth ions La³⁺, Pr³⁺,  Nd³⁺,
Sm³⁺, Gd³⁺ and  Dy³⁺ with ortho-vanillinmonoxime as the primary
ligand and 8-hydroxyquinoline(oxine), thiourea as the secondary
ligands have been prepared and characterized on the basis of their
elemental analysis, electronic, infrared and NMR spectra, thermal
analysis and conductivity measurements. A study of ultraviolet spectra
gave an evidence about complexation. Visible spectra of
Pr³⁺, Nd³⁺ and Sm³⁺ complexes indicated nepheIauxetic effect in
these complexes. The covalency parameter and  δ% covalency indicate
strong interaction of lanthanide ions and the ligands. The
shift in the characteristic infrared frequencies of free ligand band
confirms the centres of coordination. Thermal analysis indicated the
presence of coordinated water molecules. The molar conductance
in DMF and DMSO indicated that the 8-hydroxyquinoline complexes
behaved as non-electrolyte while the thiourea complcxes
behaved as 1 : 1 electrolyte system.