Rip It off: Nitro to Nitroso Reduction by Iron Half-Sandwich Complexes.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Inorganic Chemistry

Background:

• Iron complexes are versatile catalysts in organic synthesis.
• Nitroaromatic compounds are important synthetic intermediates.
• Understanding reaction mechanisms is crucial for developing new chemical transformations.

Purpose of the Study:

• To investigate the reactivity of a specific iron complex, [FeCl(dppe)Cp], with nitroaromatic compounds.
• To explore the formation of novel iron-containing complexes.
• To elucidate the reaction pathways and mechanisms involved.

Main Methods:

• Chloride abstraction from [FeCl(dppe)Cp] using sodium tetrakis(aryl)borates (Na[BArX4]).
• Reaction of the activated iron complex with various substituted nitroaromatics.
• Characterization of the resulting products using spectroscopic and analytical techniques.

Main Results:

• Synthesis of cationic iron nitroso complexes [Fe{N(O)-C6H4R}(dppe)Cp][BArX4] from diverse nitroaromatics.
• Formation of a bimetallic complex [{Fe(dppe)Cp}2{μ-N≡CC6H4N(O)}][BArF4]2.
• Isolation of the first bench-stable iron half-sandwich phenolate complex [Fe(OC6H4NO2)(dppe)Cp]+ from 4-nitrophenol.
• Proposed mechanism involving a blue bimetallic intermediate and subsequent N-O bond cleavage and C-H activation.

Conclusions:

• The iron complex [FeCl(dppe)Cp] exhibits diverse reactivity with nitroaromatics, yielding nitroso and phenolate complexes.
• A novel reaction pathway involving bimetallic intermediates and C-H activation was identified.
• The synthesized iron complexes are stable and accessible, offering potential for further synthetic applications.