Octahedral iron(iv)-tosylimido complexes exhibiting single electron-oxidation reactivity

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Bioinorganic Chemistry

Background:

• High-valent iron species are crucial in biological oxidation reactions and chemical synthesis.
• Iron(iv)-oxo complexes are well-studied, but iron(iv)-imido analogues are less common.
• Understanding the reactivity of these species is key to developing new catalytic processes.

Purpose of the Study:

• To synthesize and characterize novel octahedral iron(iv)-tosylimido complexes.
• To investigate the reactivity of these complexes as oxidants.
• To compare the reactivity of tosylimido transfer with oxo transfer.

Main Methods:

• Synthesis of iron(iv)-tosylimido complexes [Fe^IV(NTs)(L)](OTf)₂ (L = MePy₂tacn, Me₂(CHPy₂)tacn).
• Spectroscopic characterization using HR-MS, UV-vis, ¹H-NMR, resonance Raman, Mössbauer, and X-ray absorption spectroscopy.
• Computational analysis using DFT methods and X-ray crystallography for ferric decay products.

Main Results:

• Isolation and characterization of metastable iron(iv)-tosylimido complexes and their corresponding ferric complexes.
• Demonstration of tosylimido group transfer to thioanisoles, forming sulfilimines.
• Identification of hydrogen atom transfer (HAT) mechanism in reactions with hydrocarbons, with tosylimido transfer being more sensitive to charge effects than oxo transfer.

Conclusions:

• The study successfully synthesized and characterized rare iron(iv)-tosylimido complexes.
• These complexes exhibit unique reactivity, acting as effective tosylimido group transfer agents and participating in HAT reactions.
• The findings provide valuable insights into the chemistry of high-valent iron imido species and their potential applications.