Heterometallic Cu^II-Dy^III Clusters of Different Nuclearities with Slow Magnetic Relaxation

The synthesis, structures, and magnetic properties of two heterometallic Cu^II-Dy^III clusters are reported. The first structural motif displays a pentanuclear Cu^II₄Dy^III core, while the second one reveals a nonanuclear Cu^II₆Dy^III₃ core. We employed o-vanillin-based Schiff base ligands combining o-vanillin with 3-amino-1-propanol, H₂vap, (2-[(3-hydroxy-propylimino)-methyl]-6-methoxy-phenol), and 2-aminoethanol, H₂vae, (2-[(3-hydroxy-ethylimino)-methyl]-6-methoxy-phenol). The differing nuclearities of the two clusters stem from the choice of imino alcohol arm in the Schiff bases, H₂vap and H₂vae. This work is aimed at broadening the diversity of Cu^II-Dy^III clusters and to perceive the consequence of changing the length of the alcohol arm on the nuclearity of the cluster, providing valuable insight into promising future synthetic directions. The underlying topological entity of the pentanuclear Cu₄Dy cluster is reported for the first time. The investigation of magnetic behaviors of 1 and 2 below 2 K reveals slow magnetic relaxation with a significant influence coming from the variation of the alcohol arm affecting the nature of magnetic interactions.