Magnetic properties of a europium(iii) complex – possible multiplet crossover

Abstract

A dinuclear complex [(H₂O)Zn(LH)Eu(NO₃)₃] containing a hexadentate Schiff-base {N₂O₄}-donor ligand LH²⁻ was prepared and characterized by X-ray structural analysis and IR, electronic and fluorescence spectroscopy. DC magnetic data show that upon heating the diamagnetic complex with the ground state Eu(III)–⁷F₀ and Zn(II)–¹S switches to paramagnetic species due to the population of ⁷F_J (J = 1 to 6) magnetic multiplets. The magnetic susceptibility increases from zero, passes through a maximum, and then decreases upon heating. This behaviour can be explained using a spin–orbit Hamiltonian with an axial distortion term. There is an alternative interpretation of the susceptibility data based on a two-level model similar to that used in the spin crossover theory.