A study on the heterodinuclear cryptates [LnCuL(DMF)](ClO4)2·MeCN (Ln = Gd, Eu, Tb, Dy, Y) — synthesis, characterization, magnetic and electrochemical properties

Abstract

Five heterodinuclear cryptates [LnCuL(DMF)](ClO₄)₂·MeCN (Ln = Gd, Eu, Tb, Dy, Y) were synthesized (L represents the deprotonated anionic cryptand obtained by condensation of tris(2-aminoethyl)amine with 2,6-diformyl-4-chlorophenol). The ES-MS spectra of five cryptates showed that the Ln(III)–Cu(II) cores are very stable in solution. The crystal structure of [EuCuL(DMF)](ClO₄)₂ was determined and was compared with those of mono- and hetero-nuclear copper(II) with the same ligand. The Gd(III)–Cu(II) cryptate displayed weaker intramolecular ferromagnetic interactions than the complexes with two phenolate bridges. The E_1/2 values of Cu(II)/Cu(I) were influenced by Ln(III) in the cryptates and shifted negatively comparing with free Cu²⁺. The degree of negative-shift is in the order: Dy > Tb > Gd > Eu.