3d–4f Metallacrown complexes with a new sandwich core: synthesis, structures and single molecule magnet behavior†
Abstract
Two heterometallic metallacrown complexes, [Er{Cu4(butyrat)4}2]·Cl3·MeOH·26H2O (1) and [Yb{Cu4(butyrat)4}2]·Cl3·MeOH·26H2O (2) (H2butyrat = 3-aminobutyric hydroxamic acid), have been reported. X-ray crystallographic analysis reveals that the two complexes displayed nested-sandwich configurations with two 12-MC-4 metallacrown units capping LnIII in the centre. Magnetic studies revealed that 1–2 undergo antiferromagnetic coupling interaction. Magnetic measurements show that complex 2 displays frequency-dependent signals at a dc field of 1000 Oe, indicating field-induced single-molecule magnet behavior.