Single-molecule magnets (SMMs) are metal-organic complexes which can retain a magnetization after the magnetic field which was used to induce it is turned off. Below the so-called blocking temperature, the relaxation of the magnetization in such systems becomes slow and the total spin remains stable for a time. Polynuclear Fe(II) SMMs are difficult to synthesize and, thus, rare.
Yuan-Zhu Zhang and colleagues, Southern University of Science and Technology, Shenzhen, China, have synthesized a linear trinuclear Fe(II) single-molecule magnet. The team reacted FeCl2·4H2O with the ligand 2-[(pyridine-2-ylimine)-methyl]phenol (Hpymp) in methanol under an argon atmosphere and added NaBPh4. They obtained crystals of the complex [FeII3(pymp)4(MeOH)2][BPh4]2·2MeOH (pictured).
The complex was characterized using X-ray diffraction, which showed a linear Fe3-chain connected by four [pymp]− ligands. Magnetic measurements provided evidence for a ferromagnetic coupling within the Fe3-chain, for a magnetic anisotropy in the molecule, and for the single-molecule-magnet character of the complex.
- A Linear Trinuclear Ferrous Single Molecule Magnet,
Shi-Hao Liu, Yi-Fei Deng, Chang’An Li, Xiaoyong Chang, Yuan-Zhu Zhang,
Dalton Trans. 2018.