A Caged Neutral 17-Valence-Electron Iron(I) Radical [Fe(CO)₂(Cl)(P((CH₂)₁₀)₃P)]^•: Synthetic, Structural,...

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Radical Chemistry

Background:

• Investigating the synthesis and properties of novel iron complexes.
• Exploring the formation of isolable iron(I) radical species.

Purpose of the Study:

• To synthesize and characterize a rare trigonal-bipyramidal iron(I) radical complex.
• To elucidate the structural, redox, and spectroscopic properties of the synthesized complex.
• To understand the influence of ligand chain length on complex formation.

Main Methods:

• UV irradiation of iron precursors in dichloromethane.
• X-ray crystallography for structural determination.
• Magnetic susceptibility measurements (Evans' method, SQUID).
• Cyclic voltammetry for redox property analysis.
• Spectroscopic techniques (UV-visible, EPR, 57Fe Mössbauer).
• Density Functional Theory (DFT) calculations.

Main Results:

• Successful synthesis of the iron(I) radical complex trans-[Fe(CO)2(Cl)(P((CH2)10)3P)]• (1a•) in 31% yield.
• Crystallographic analysis confirmed a trigonal-bipyramidal structure for 1a•.
• Magnetic studies indicated a spin of 1/2, consistent with a radical species.
• Cyclic voltammetry revealed a partially reversible one-electron oxidation for 1a•.
• Analogous precursors with longer phosphine ligands yielded only demetalated diphosphines.

Conclusions:

• The study reports a rare isolable iron(I) radical complex with unique structural and electronic properties.
• The findings provide valuable insights into the formation and characterization of low-valent iron species.
• Ligand chain length plays a critical role in directing the outcome of the photochemical reaction.