Synthesis and characterization of some hexa and nona-coordinated complexes of trivalent lanthanides(III) derived from 4[N-(4′-dimethylaminobenzalidene)amino] antipyrine semicarbazone

In this paper, we report the synthesis and study of lanthanide(III) perchlorates and nitrates complexes of 4[N-(4'-dimethylamino-benzalidene)amino]antipyrine semicarbazone (DABAAPS). The complexes are of the type LnX(3).n(DABAAPS) (X = ClO4, n = 2; X = NO3, n = 1; Ln = La, Pr, Nd, Sm, Gd, Th, Dy or Ho) and have been characterized on the basis of elemental analyses, conductance measurements, magnetic moments, thermal analyses, infrared and electronic spectra. Their nephelauxtic (beta), covalency factor (b(1/2)), Sinha's parameter (delta%) and angular overlap parameter (eta) have been determined for the Pr(III), Nd(III), Sm(III) and Ho(III) complexes, which indicate some covalent character in these complexes.