The structure and reactivity of iron nitride complexes

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Inorganic Chemistry

Background:

• Discrete iron nitride complexes are crucial in understanding nitrogen fixation and catalysis.
• Previous studies focused on cryogenic characterization of thermally unstable six-coordinate iron nitrides.
• The reactivity and stability of different iron nitride structures remained an area for exploration.

Purpose of the Study:

• To describe the structure and reactivity of discrete iron nitride complexes.
• To investigate the properties of four-coordinate, three-fold symmetric iron nitrides.
• To explore the catalytic potential of iron nitrides in nitrogen atom transfer and ammonia synthesis.

Main Methods:

• Synthesis and characterization of iron nitride complexes.
• Spectroscopic methods for analyzing complex structures.
• Reactivity studies involving nitrogen atom transfer to various substrates.
• Electrochemical oxidation to generate higher oxidation state iron nitrides.

Main Results:

• Six-coordinate iron nitrides are thermally unstable, requiring cryogenic temperatures for characterization.
• Four-coordinate iron nitrides are stable at room temperature and can be isolated.
• Tris(carbene)borate iron(IV) nitrides exhibit reactivity in two-electron nitrogen atom transfer and single-electron pathways.
• Ammonia synthesis was achieved via a mechanism involving hydrogen atom transfer to the nitride ligand.
• One-electron oxidation yielded an isolable and highly reactive iron(V) nitride complex.

Conclusions:

• Room-temperature stable iron nitrides, particularly four-coordinate variants, offer accessible platforms for studying nitrogen chemistry.
• These iron nitrides demonstrate significant potential as catalysts for nitrogen atom transfer and ammonia synthesis.
• The discovery of a reactive iron(V) nitride expands the known reactivity landscape of metal nitrides.