Studies on some lanthanide(III) complexes with 4-hydroxyantipyrine

Seven new lanthanide(III) complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR spectra, X-ray powder diffraction, and thermogravimetric studies. The ligand, 4-hydroxyantipyrine (hap), contained carbonyl oxygen and hydroxyl oxygen as potential donor sites. On coordination, deprotonation occurred and as a result, hap acted as a monobasic bidentate ligand. A coordination number 6 was assigned to the lanthanide(III) ions in these complexes with orthorhombic structure. All the complexes were thermally stable ∼150 °C and underwent decomposition in three stages with the formation of Ln2O3 as the final residues.