A Terminal Imido Complex of an Iron-Sulfur Cluster

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Iron-sulfur (Fe-S) clusters are crucial in biological systems and catalysis.
• Terminal imido ligands are synthetically challenging to incorporate into Fe-S clusters.
• Oxidative group transfer reactions are key for functionalizing metal clusters.

Purpose of the Study:

• To synthesize and characterize the first terminal imido complex of an Fe-S cluster.
• To investigate the electronic structure and bonding of the Fe-imido moiety.
• To assess the reactivity of the new complex, particularly in C-H activation.

Main Methods:

• Synthesis of the imido complex via oxidative group transfer from DippN3 to an all-ferrous Fe-S cluster.
• Characterization using structural (X-ray diffraction), spectroscopic (e.g., Mössbauer, EPR), and computational methods.
• Reactivity studies involving hydrogen atom abstraction from 1,4-cyclohexadiene.

Main Results:

• Successful synthesis of the terminal imido complex (IMes)3Fe4S4=NDipp.
• Structural and spectroscopic data indicate a high-spin Fe(III) center at the imido-bound site.
• The complex exhibits reactivity towards C-H activation, forming an anilido complex.

Conclusions:

• The first terminal imido complex of an Fe-S cluster has been synthesized and fully characterized.
• The Fe-imido linkage is best described as involving a high-spin Fe(III) center.
• This Fe-S imido complex demonstrates potential for catalytic applications, including C-H activation.