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High-Spin [FeI3] Cluster Capable of Pnictogen Atom Capture.
Trevor P Latendresse1, Nicholas P Litak1, Joy S Zeng1
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
Journal of the American Chemical Society
|September 4, 2024
Summary
This study introduces a novel hexanuclear iron cluster ([Fe3]) capable of multielectron redox chemistry. The iron cluster mediates atom transfer reactions and exhibits unique magnetic properties, including single-molecule magnetism.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Magnetochemistry
Background:
- Development of polynuclear clusters with tunable electronic and magnetic properties is crucial for advanced applications.
- Low-valent iron clusters offer unique reactivity and magnetic behavior due to accessible redox states.
Purpose of the Study:
- To synthesize and characterize a novel all-monovalent [Fe3] cluster using a hexanucleating anildophosphine ligand.
- To investigate the multielectron redox chemistry and magnetic properties of the synthesized iron cluster and its derivatives.
- To explore the potential of these clusters in mediating atom transfer reactions and as single-molecule magnets.
Main Methods:
- Synthesis of a hexanucleating anildophosphine ligand (LH3) and the all-monovalent [Fe3] compound ((L)Fe3, 1).
- Characterization using X-ray diffraction, SQUID magnetometry, 57Fe Mössbauer spectroscopy, and cyclic voltammetry.
- Investigation of multielectron oxidative atom transfer reactions with azide, cyanate, and phosphonate precursors.
- AC SQUID magnetometry to study magnetic relaxation dynamics.
Main Results:
- Isolation and full characterization of the all-monovalent [Fe3] compound (1) with short Fe-Fe distances and high spin state (S=9/2).
- Compound 1 successfully mediated multielectron oxidative atom transfer to form [Fe3]-nitrido (2) and [Fe3]-phosphido (3) pnictides.
- Compounds 1-3 displayed rich electrochemical behavior with multiple distinct redox events.
- Compound 3 exhibited single-molecule magnet behavior with a significant energy barrier for relaxation reversal (U=30.7(6) cm-1) in zero field.
Conclusions:
- The study demonstrates the utility of an all low-valent polynuclear iron cluster for performing complex multielectron redox chemistry.
- The synthesized iron clusters exhibit significant redox flexibility and unique magnetic properties, including single-molecule magnetism.
- This work opens avenues for designing advanced polynuclear clusters with tailored reactivity and magnetic functionalities.
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