Syntheses, structures and magnetic properties of macrocyclic Schiff base-supported homodinuclear lanthanide complexes

Abstract

Five new homodinuclear lanthanide complexes with the general formula [(acac)₄Ln₂(L)] (Ln³⁺ = Dy³⁺ (1), Tb³⁺ (2), Ho³⁺ (3), Er³⁺ (4), and Gd (5)) were synthesized by one-pot [2 + 2] condensation of 2,6-diformyl-4-methylphenol and 1,3-diaminopropane in the presence of various lanthanide acetylacetonates. The eight-coordinate Ln(III) centre adopts a slightly distorted square antiprism geometry with D_4d symmetry. Theoretical analysis and magnetic measurements reveal that the corresponding Dy complex 1 exhibits slow magnetic relaxation behavior, characteristic of a typical SMM with the intramolecular ferromagnetic Dy³⁺⋯Dy³⁺ interaction.