Dynamic Magnetic and Optical Insight into a High Performance Pentagonal Bipyramidal Dy III Single-Ion Magnet.

The pentagonal bipyramidal single-ion magnets (SIMs) are among the most attractive prototypes of high-performance single-molecule magnets (SMMs). Here, a fluorescence-active phosphine oxide ligand CyPh2 PO (=cyclohexyl(diphenyl)phosphine oxide) was introduced into [Dy(CyPh2 PO)2 (H2 O)5 ]Br3 ⋅2 (CyPh2 PO)⋅EtOH⋅3 H2 O, and combined dynamic magnetic measurement, optical characterization, ab initio calculation, and magneto-optical correlation of this high-performance pseudo-D5h DyIII SIM with large Ueff (508(2) K) and high magnetic hysteresis temperature (19 K) were performed. This work provides a deeper insight into the rational design of promising molecular magnets.