Field-induced single-molecule magnetism in aminyl radical bridged trinuclear lanthanide clusters

Lanthanide single-molecule magnets (Ln-SMMs) are considered potential candidates for constructing nanoscale magnetic devices. Previous studies have demonstrated that the delocalized radical bridges can potentially induce strong magnetic exchange and suppress the QTM. In this work, we report a series of isostructural trinuclear lanthanide complexes 1-Ln bridged by aminyl radicals (-[NH]•-). Magnetic studies reveal that 1-Dy and 1-Er behave as field-induced SMMs, with their relaxation following the Orbach mechanism, while 1-Tb only exhibits field-induced magnetic relaxation. Ab initio calculations demonstrate that the three inequivalent DyIII sites possess different coordination distortion degrees, non-collinear easy axes and diverse spin state compositions. Their large ground-state transverse magnetic moments trigger intrinsic QTM and block relaxation via excited states. This work unveils the unique structure and the distinct magnetic coupling mode of the -[NH]•- radical bridge, providing insights for designing funtioncal magnetic materials by introducing new radical bridges.