A series of Salen‐type homodinuclear lanthanide complexes and their slow magnetic relaxation in Dy2 and Ho2

Abstract

A series of homodinuclear lanthanide complexes, namely, [Ln2(L)2(MeOH)2(NO3)2] [Ln = Gd (1), Tb (2), Dy (3), and Ho (4)], were synthesized by the reaction of Salen‐type ligand, namely N, N′‐bis(5‐bromosalicylidene)ethane‐1,2‐diamine (H2L), with lanthanide salts in methanol and acetonitrile solution. The two LnIII ions in 1–4 are linked by two Ophenoxo atoms of two L2− ligands to build a dinuclear skeleton. The eight‐coordinate LnIII center adopts a triangular dodecahedron geometry of D2d symmetry. Theoretical calculations revealed that antiferromagnetic interactions exist in those complexes. Dynamic magnetic properties studies indicate that the Dy2 complex behaves as a single‐molecule magnet with an anisotropy barrier of Ueff ≈ 47.68 K and a pre‐exponential factor τ0 = 3.17 × 10−6 s under a zero applied field, whereas the Ho2 complex exhibits a fast tunneling relaxation process that is rationalized through ab initio calculations.