Single-Molecule-Magnet Behavior in a [2 × 2] Grid Dy^III₄ Cluster and a Dysprosium-Doped Y^III₄ Cluster

Thanks to the MeCN hydrolysis in situ reaction, a [2 × 2] square grid Dy^III₄ cluster based on a polypyridyl triazolate ligand, [Dy₄(OH)₂(bpt)₄(NO₃)₄(OAc)₂] (<b>1</b>), was separated successfully and characterized through single-crystal X-ray diffraction and SQUID magnetometry. The frequency-dependent signals in the out-of-phase component of the susceptibility associated with slow relaxation of the magnetization confirmed that complex <b>1</b> displays single-molecule magnet (SMM) behavior. Two distinct slow magnetic relaxation processes, with effective energy barriers <i>U</i>_eff1 = 93 cm^–1 for fast relaxation and <i>U</i>_eff2 = 143 cm^–1 for slow relaxation observed under a zero direct-current field, are mainly attributed to the origin of single-ion behavior, which can be further acknowledged by the magnetic investigation of a dysprosium-doped yttrium cluster. Besides, it should be noted that complex <b>1</b> represents so far the highest energy barrier among the pure Dy^III₄ SMMs