Chelating Behaviour of 4[N-(Benzylidene)amino]-antipyrine Semicarbazone Towards Lanthanide Ions

A series of lanthanide(III) nitrate chelates of 4[N-(benzylidene)amino]antipyrine semicarbazone (BAAPS) with the general composition [Ln(BAAPS) (NO3)3] (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy or Ho) have been synthesized in ethanol. All chelates were characterized on the basis of element analyses, conductance measurements, magnetic moments, infrared and electronic spectra. Their nephelauxetic ratios (β), covalency factors (b½), Sinha parameters (δ %) and angular overlap parameters (η) have been calculated for the Pr(III), Nd(III) and Sm(III) complexes, which indicate some covalent character of these complexes. Thermal stabilities of the complexes were also studied.