Magnetostructural correlation in isolated trinuclear iron(iii) oxo acetate complexes

Area of Science:

• Inorganic Chemistry
• Physical Chemistry
• Computational Chemistry

Background:

• Trinuclear iron(iii) oxo acetate complexes are model systems for studying magnetic exchange interactions.
• Understanding the relationship between structure and magnetism is crucial for designing new magnetic materials.

Purpose of the Study:

• To investigate the correlation between geometric structure and magnetic couplings in gaseous iron(iii) oxo acetate ions.
• To determine how pyridine ligand coordination affects the magnetic properties of these complexes.

Main Methods:

• Infra Red-Multiple Photon Dissociation (IR-MPD) and Collision Induced Dissociation (CID) experiments were used for structural analysis.
• Density Functional Theory (DFT) calculations with a Broken Symmetry approach were employed to simulate magnetic couplings.
• Antiferromagnetic coupling constants were extracted and analyzed.

Main Results:

• Coordination of pyridine ligands distorts the Fe3O core geometry, affecting Fe-Ocentral bond lengths.
• Antiferromagnetic coupling constants varied from -62 cm-1 to -28 cm-1 with increasing pyridine coordination.
• Pyridine coordination induced a switching of magnetic ground states, with total spin (ST) changing from 1/2 to 3/2 and 5/2, and back to 1/2.

Conclusions:

• Geometric distortions driven by pyridine coordination directly influence the magnetic exchange interactions in these iron complexes.
• The study demonstrates a clear mechanism for controlling magnetic ground states through ligand coordination.
• This work provides insights into the design of switchable magnetic materials based on polynuclear metal complexes.