Synthesis, characterization, thermal and electrical properties of yttrium(III) and lanthanide(III) complexes of salicylaldehyde benzoyl hydrazone

Complexes of Y(III), La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III) with salicylaldehyde benzoyl hydrazone, (C6H5CONHN=CHC6H4OH), abbreviated as H2L, have been synthesized and characterized. The analytical data are suggestive of 2:3 metal : ligand stoichiometry in the complexes except in the case of Y(III), which is a 1:1 complex. A dehydration study at two temperatures, 110 degrees C and 150 degrees C, indicates water molecules both in the lattice and co-ordination sphere of the metal ions. Magnetic moments, IR spectra, electronic spectra and H-1 NMR spectra have been recorded to establish the bonding sites of the ligand. The complexes are coloured, soluble in methanol, dimethyl sulfoxide, dimethyl formamide and insoluble in benzene, chloroform and acetonitrile. Solid state conductance at various frequencies shows the semiconducting nature of the complexes. Solution state conductance indicates their non-electrolyte nature. Optical band gap measurements on a representative complex, Dy-2(L)(3). 12H(2)O show that the complex is a direct band gap material. X-ray analyses show that the structures of most of the complexes are orthorhombic.