Optimized single molecule magnet in double-decker hetero-metallic complexes

•Two hetero-metallic complexes supported by salen-type and β-diketonate ligands.•The Ln3+ ion is of a typical double-decker sandwich structure.•Both of complexes 1 and 2 exhibit single molecule magnet behaviour.•The energy barrier of complex 1 is 40.1 K under an optimal external field.

Two new hetero-metallic complexes [LnNa2(L)2(bta)(CH3OH)]∙nH2O∙mCH3OH (Ln = Dy (1), n = 1, m = 0; Er (2), n = 0, m = 1) supported by rigid hexadentate salen-type (H2L = N,N′-bis(2-oxy-3-methoxybenzylidene)-1,2-phenylenediamine) and β-diketonate (bta = benzoyltrifluoroacetone) ligands have been designed and synthesized. Structural analysis reveals that the Ln3+ ion has a typical double-decker sandwich structure with a distorted bicapped triangular prism. The magnetic analysis unveils that both complexes 1 and 2 are of single molecule magnet behavior, and both of them can be regarded as rare SMMs based on the salen-type ligand with a double-decker structure.