Mixed-Valence Iron Complexes Containing End-On Bridging Cyaphide Ions

Area of Science:

• Coordination chemistry
• Organometallic chemistry
• Inorganic synthesis

Background:

• Iron cyanide compounds are historically significant synthetic coordination compounds.
• Iron complexes with the cyaphide ion (C≡P⁻), a cyanide analog, were previously unknown.
• The cyaphide ion (C≡P⁻) is a heavy valence isoelectronic analog of the cyanide ion (C≡N⁻).

Purpose of the Study:

• To synthesize and characterize novel iron complexes of the cyaphide ion.
• To explore the coordination behavior of cyaphide ligands with iron.
• To investigate the formation of multimetallic complexes involving iron cyaphides.

Main Methods:

• Synthesis of iron(II) cyaphide complexes: Fe(depe)2(Cl)(CP) and Fe(depe)2(CP)2.
• Utilizing 1,2-bis(diethylphosphino)ethane (depe) as a supporting ligand.
• Characterization of novel iron-cyaphide coordination geometries and multimetallic structures.

Main Results:

• Successful synthesis of stable mono- and bis-cyaphide iron(II) complexes.
• Demonstration of cyaphide ligand's ability to bridge iron centers.
• Formation of unprecedented linear coordination geometries for iron(I) species.
• Synthesis of conjugated multimetallic mixed-valence iron complexes.

Conclusions:

• Established the existence and stability of iron cyaphide complexes.
• Revealed a novel linear coordination mode for iron(I) facilitated by cyaphide ligands.
• Expanded the scope of known multimetallic coordination compounds with conjugated systems.