Slow magnetization dynamics in a six-coordinate Fe(ii)-radical complex

Area of Science:

• Coordination Chemistry
• Materials Science
• Magnetism

Background:

• Development of novel paramagnetic ligands is crucial for advancing molecular magnetism.
• Dithiadiazolyl ligands offer unique electronic properties for magnetic exchange.
• Iron complexes are widely studied for their magnetic characteristics.

Purpose of the Study:

• To synthesize and characterize a new paramagnetic ligand, betaDTDA (4-(benzothiazol-2'-yl)-1,2,3,5-dithiadiazolyl).
• To investigate the magnetic properties of its coordination complex with Fe(hfac)2 (1,1,1,5,5,5-hexafluoroacetylacetonato).
• To explore the potential for single-molecule magnet (SMM) behavior.

Main Methods:

• Synthesis of the betaDTDA ligand and its Fe(hfac)2 complex.
• X-ray crystallography to determine the complex's structure.
• Magnetic susceptibility measurements (dc and ac) to probe magnetic interactions and relaxation dynamics.

Main Results:

• The Fe(hfac)2(betaDTDA) complex features a high-spin Fe(II) center in a distorted octahedral environment.
• Strong antiferromagnetic (AF) coupling between metal and ligand moments was observed.
• A well-defined Stotal = 3/2 ground state was established, stable below 40 K.
• Single-molecule magnet (SMM) behavior, indicated by slow magnetization relaxation, was detected below 4 K.

Conclusions:

• The novel betaDTDA ligand facilitates strong magnetic exchange interactions.
• The Fe(hfac)2(betaDTDA) complex demonstrates promising single-molecule magnet properties.
• This work expands the scope of dithiadiazolyl ligands in molecular magnetism.