Ligand Redox Reactivity Supports C-F Activation at Al(III).

Area of Science:

• Organometallic Chemistry
• Fluorine Chemistry
• Organic Synthesis

Background:

• Carbon-fluorine (C-F) bond activation is crucial for organic synthesis.
• Existing methods include electron reduction and fluoride abstraction.
• Low-valent aluminum(I) complexes activate C-F bonds via oxidative addition.

Purpose of the Study:

• To report a new method for stoichiometric C-F bond activation in aryl-CF3 compounds.
• To investigate the role of ligand redox chemistry in C-F bond activation using an Al(III) complex.

Main Methods:

• Stoichiometric reaction of an Al(III) complex with aryl-CF3 compounds.
• Synthesis and characterization of possible intermediates, including radical species and fully oxidized complexes.
• Utilizing a diiminepyridine ligand (PhI2P) that undergoes a two-electron redox change.

Main Results:

• Successful stoichiometric activation of C-F bonds in aryl-CF3 compounds.
• Observed a two-electron ligand-based oxidation coupled with the formation of two Al-F bonds.
• Synthesized and characterized key intermediates: (PhI2P-)AlF2 and [(PhI2P0)AlI2]+.

Conclusions:

• The study demonstrates a novel Al(III)-mediated C-F bond activation pathway.
• Highlights the critical role of ligand redox non-innocence in facilitating C-F bond cleavage.
• Provides insights into the mechanism linking ligand redox behavior to C-F bond activation efficacy.