Field-Induced Slow Relaxation in a Monometallic Manganese(III) Single-Molecule Magnet

High-field electron paramagnetic resonance spectroscopy shows that the structurally distorted MnIII ion in Na5[Mn­(l-tart)2]·12H2O (1; l-tart = l-tartrate) has a significant negative axial zero-field splitting and a small rhombic anisotropy (∼1% of D). Alternating-current magnetic susceptibility measurements demonstrate that 1, which contains isolated MnIII centers, displays slow relaxation of its magnetization under an applied direct-current magnetic field.