Isolation and characterization of a high-spin mixed-valent iron dinitrogen complex

Area of Science:

• Inorganic Chemistry
• Materials Science
• Magnetochemistry

Background:

• Mixed-valence compounds exhibit unique electronic and magnetic properties.
• Iron-nitrogen cores are crucial in various catalytic and magnetic materials.
• Understanding electron delocalization is key to tuning material properties.

Purpose of the Study:

• To synthesize and characterize a rare mixed-valence iron compound with an FeNNFe core.
• To investigate the structural, spectroscopic, and magnetic effects of single-electron reduction/oxidation.
• To elucidate the nature of electron localization and backbonding in the FeNNFe system.

Main Methods:

• Synthesis of the novel mixed-valence iron compound.
• Mössbauer spectroscopy at 80 K to assess electron localization.
• Infrared spectroscopy at room temperature for vibrational analysis.
• Magnetic susceptibility and relaxation studies to probe magnetic behavior.

Main Results:

• A rare mixed-valence iron compound featuring an FeNNFe core was successfully synthesized.
• Mössbauer and infrared spectra indicate the odd electron is localized.
• The N2 backbonding is intermediate between diiron(I) and diiron(0) states.
• Magnetic studies reveal significant anisotropy but rapid relaxation via through-barrier pathways.

Conclusions:

• The synthesized compound provides a model for understanding electron transfer in mixed-valence iron systems.
• Electron localization and intermediate backbonding influence the compound's properties.
• Despite magnetic anisotropy, rapid relaxation is observed, relevant for magnetic materials applications.