Modulating the Slow Relaxation Dynamics of Binuclear Dysprosium(III) Complexes through Coordination Geometry

A class of two dinuclear dysprosium based complexes 1 and 2 were synthesized by employing salicyloylhydrazone derived pentadentate ligand (L). Structural analysis reveals that in complex 1, two DyIII centers are in muffin (Cs) coordination geometry while in 2, one DyIII center is in bicapped square antiprism (D4d) and other one is in triangular dodecahedron (D2d) coordination geometry. AC magnetic susceptibility measurements disclose that complexes 1 and 2 exhibit single-molecule magnet (SMM) behavior, with effective energy barrier of 36.4 and 9.7 K, respectively. The overall studies reveal that small differences in the coordination environment around the DyIII centers played a significant role in the difference in relaxation dynamics of the complexes. In order to elucidate the role of intermolecular interactions between nearby DyIII centers in the magnetic relaxation behavior, a diamagnetic isostructural YIII analog (3) was synthesized and magnetic behavior was examined