Dinuclear Lanthanide–Carboxylate Compounds: Field-Induced Slow Relaxation of Magnetization for Dysprosium(III) Analogue

Abstract

Three chiral dinuclear lanthanide compounds, Ln2(µ2-L)4(L)2(phen)2 (Ln = Dy (1), Gd (2), and Er (3); phen = 1,10-phenanthroline), have been synthesized using the (S)-(+)-2-(6-methoxy-2-naphthyl)propionic acid (HL) ligand. The two lanthanide centres in compound Ln2(µ2-L)4(L)2(phen)2 are bridged by four carboxylate groups to give a dinuclear Ln2(µ2-L)4 core. The square antiprismatic coordination environment for each lanthanide centre is further completed by a chelating carboxylate group from another L– ligand and two nitrogen atoms from the phen ligand. A weak antiferromagnetic interaction between the two GdIII ions is observed in compound 2. The Dy analogue displays field-induced slow magnetic relaxation behaviour with an effective energy barrier Ueff/k of 17.24(2) K and a pre-exponential factor τ0 of 2.7(1) × 10–6 s. However, no slow relaxation phenomenon was observed for the Er derivative even in the presence of 2 kOe applied field.