Synthesis and Magnetic Properties of Mn12-Based Single Molecular Magnets with Benzene and Pentafluorobenzene Carboxylate Ligands

We report on the synthesis and magnetic properties of Mn12-based single molecular magnets (SMMs) with benzene and pentafluorobenzene carboxylate ligands. The changes in ligand structure are shown to have a decisive effect on the magnetic properties of the complexes produced. The compound with benzene demonstrates an unusual magnetic behavior, namely, temperature dependencies of magnetization taken under the zero-field-cooled and field-cooled conditions are split below 10 K and furthermore remnant magnetization and coercive force remain nonzero in this temperature range. In contrast, the compound with pentafluorobenzene displays the customary signatures of the blocking temperature at 3 K. The effect of ligand substitution was theoretically studied within the local density approximation taking into account on-site Coloumb repulsion. Calculation results confirm that the electronic structure and the magnetic exchange interactions between different Mn atoms strongly depend on the type of ligand.