Studies on some rare earth metal complexes: Ten- and six-coordinated complexes of an unsymmetrical aminoacid derivative

Abstract

2,4-Dihydroxybenzaldehyde(N-benzoyl)glycyl hydrazone, H3 dhbbgh, has been synthesized and characterized. Rare earth metal complexes of the empirical formulae, [Ln(H3dhbbgh)2Cl2]Cl.nH2O and [Ln(dhbbgh)(H2O)2], where Ln=La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III) and Y(III) have been synthesized and characterized by elemental analyses, molar conductances, magnetic susceptibilities, electronic, infrared and NMR spectral studies. Various bonding parameters (β, b1/2, %δ andη) calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes suggest a weak covalent bond between the metal and ligand. The theoretical oscillator strengths (Pcalcd) and a set of three intensity parameters (Tλ=2,4.6) computed from the Judd-Ofelt equation are found to be in good agreement with experimental values. On the basis of the spectral profiles of the hypersensitive transitions (4I9/2→4G5/2,2G7/2) in the Nd(III) complexes, coordination numbers ten and six have been proposed for the Ln(III) ions in the adduct and deprotonated complexes respectively.