Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

Area of Science:

• Organometallic Chemistry
• Computational Chemistry

Background:

• The electronic structure of metallacycles is crucial for understanding their reactivity.
• Isolated monometallic iron azametallacyclobutene complexes represent a novel class of compounds.

Purpose of the Study:

• To investigate the electronic structure of the first isolated monometallic iron azametallacyclobutene complex.
• To elucidate the bonding characteristics and reactivity of this novel metallacycle.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to analyze the electronic structure.
• Experimental observations were used to validate computational findings.

Main Results:

• DFT calculations revealed significant electron delocalization within the four-atom ring system.
• A substantial contribution from an imine-substituted iron carbene resonance structure was identified.
• The complex exhibits carbene-like reactivity, demonstrated by its reaction with isocyanide to form a ketenimine.
• Reaction with carbon monoxide yielded a five-membered metallacycle, confirming α-carbon reactivity.

Conclusions:

• The iron azametallacyclobutene complex is a conjugated metallacycle with delocalized electrons.
• The bonding is influenced by an iron carbene resonance structure.
• The complex displays predictable carbene-like reactivity at the α-carbon.