Iron(II) Complexes Featuring a Redox-Active Dihydrazonopyrrole Ligand

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Synthetic Chemistry

Background:

• Metal-ligand cooperativity is a key strategy in synthetic chemistry for mediating challenging transformations.
• NNN pincer ligands are well-established, but ligands capable of both proton and electron transfer are less common.
• Dihydrazonopyrrole (DHP) ligands show tunable redox and protonation states with Nickel, but this is less clear with other metals.

Purpose of the Study:

• To synthesize and characterize new iron-dihydrazonopyrrole (Fe-DHP) complexes.
• To investigate the redox behavior and electronic structure of these Fe-DHP complexes.
• To explore the potential for enhanced reactivity offered by the coordination environment.

Main Methods:

• Synthesis of a new series of iron complexes featuring dihydrazonopyrrole (DHP) ligands.
• Isolation of complexes in two distinct oxidation states.
• Detailed characterization techniques to elucidate electronic structure and coordination geometry.

Main Results:

• Successful synthesis of two distinct oxidation states of Fe-DHP complexes.
• Characterization confirms that the redox activity is primarily ligand-based.
• The complexes are five-coordinate with an available open coordination site.

Conclusions:

• The synthesized Fe-DHP complexes exhibit ligand-based redox chemistry.
• The five-coordinate nature and open site suggest potential for further reactivity.
• This work expands the understanding of DHP ligand behavior with first-row transition metals.