tuning of hula-hoop coordination geometry in a dy dimer

The reaction of DyCl3 with hydrazone Schiff base ligands and sodium acetate in the presence of triethylamine (Et3N) as base affords two dysprosium dimers: [Dy2(HL1)2(OAc)2(EtOH)(MeOH)] (1) and [Dy2(L2)2(OAc)2(H2O)2]·2MeOH (2). The DyIII ions in complexes 1 and 2 are linked by alkoxo bridges, and display “hula hoop” coordination geometries. Consequently, these two compounds show distinct magnetic properties. Complex 1 behaves as a field-induced single molecule magnet (SMM), while typical SMM behavior was observed for complex 2. In addition, comparison of the structural parameters among similar Dy2 SMMs with hula hoop-like geometry reveals the significant role played by coordination geometry and magnetic interaction in modulating the relaxation dynamics of SMMs.