Electronic Structure of a Mixed-Metal Fluoride-Centered Triangle Complex: A Potential Qubit Component

Area of Science:

• Coordination chemistry
• Inorganic materials science
• Magnetochemistry

Background:

• Carboxylate complexes offer versatile platforms for designing novel metal-containing materials.
• Fluoride ligands can mediate unique magnetic interactions in polynuclear metal clusters.
• Nickel-chromium systems are of interest for their diverse magnetic properties.

Purpose of the Study:

• To synthesize and characterize a novel fluoride-centered triangular-bridged nickel-chromium carboxylate complex.
• To investigate the effect of postsynthetic ligand substitution on the structural and magnetic properties.
• To elucidate the magnetic interactions and ground state properties of the synthesized complexes.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Magnetic susceptibility measurements (SQUID magnetometry).
• Analysis of magnetic data to determine magnetic interactions and ground state.

Main Results:

• A novel triangular-bridged complex [Ni2Cr(μ3-F)(O2C(t)Bu)6(HO2C(t)Bu)3] (1) was synthesized.
• Postsynthetic substitution with pyridine and 4-methylpyridine yielded complexes 2 and 3.
• A dominating antiferromagnetic interaction was observed between Ni and Cr centers, resulting in an S = 1/2 ground state.

Conclusions:

• The synthesized fluoride-centered complex and its derivatives exhibit interesting structural and magnetic behaviors.
• Ligand substitution can tune the properties of these polynuclear complexes.
• The observed antiferromagnetic coupling and unusual g-value (geff = 2.48) highlight the unique electronic environment dictated by the fluoride bridge.