Synthesis and physicochemical studies of yttrium and lanthanide nitrate complexes of 1,2-(diimino-4′-antipyrinyl)ethane

Abstract

Yttrium and lanthanide nitrate complexes of the Schiff base, 1,2-(diimino-4'-antipyrinyl)ethane (GA), of the type [Ln(GA)2 (NO 3)a ] (where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho or Er) have been synthesised and characterised by elemental analyses, electrical conductance, magnetic susceptibility, infrared, proton NMR and electronic spectra, and thermogravimetric studies. Infrared and proton NMR spectra of these complexes show that GA acts as a neutral tetradentate ligand and that all the three nitrate groups are coordinated monodentate!y. The electronic spectra of the Pr, Nd, Ho and Er complexes suggest reasonable covalency in the metal~ligand bond. The magnetic moments of these complexes are in agreement with the van Vleck values. All these complexes are thermally stable up to about 200°C. A coordination number of eleven may be assigned to the metal ions in these complexes.