Rare Earth Nitrate Complexes with an ONO Schiff Base Ligand: Spectral, Thermal, Luminescence and Biological Studies

Five rare earth complexes lanthanum(III),praseodymium(III),neodymium(III), samarium(III) and europium(III) have been synthesized from Schiff base ligand (N,N-bis (2-hydroxy-1-naphthylidene) acetylhydrazone). The complexes were characterized based on elemental analysis, molar conductance, ultraviolet, infrared, mass, thermogravimetric and powder X-ray diffraction studies. Infrared spectra suggest ligand act as a neutral tridentate ligand. The Schiff base ligand coordinating through the naphtholic oxygen without proton displacement, azomethine nitrogen atom and hydrazone carbonyl oxygen atoms of the ligand to the lanthanide ion. The conductivity and thermal decomposition studies indicate the presence of two coordinated nitrate ion acts as bidentate fashion. Powder X-ray diffraction studies reveal the neodymium complex has an orthorhombic system with different unit cell parameters. Europium, samarium, neodymium and praseodymium complexes exhibit the characteristic luminescence. Further, the in vitro antimicrobial activities of the metal complexes exhibited greater activity as compared with the ligand.