An aldehyde-stabilised alkoxyaluminium dication

Area of Science:

• Organometallic Chemistry
• Fluorine Chemistry
• Catalysis

Background:

• Aluminum compounds exhibit diverse Lewis acidity and reactivity.
• Perfluoroalkyl groups significantly alter electronic and steric properties of metal complexes.
• Aldehyde ligands can coordinate to metal centers, influencing reactivity.

Purpose of the Study:

• To synthesize and characterize a novel perfluoro-tert-butoxyaluminum dication stabilized by aldehyde ligands.
• To investigate the Lewis acidic reactivity of the synthesized dication.
• To explore the potential of the aluminum center in catalytic transformations.

Main Methods:

• Synthesis of the perfluoro-tert-butoxyaluminum dication using specific precursors.
• Structural characterization using spectroscopic and crystallographic techniques.
• Reactivity studies involving treatment with triethylsilane and subsequent catalytic testing.

Main Results:

• Successful synthesis and structural elucidation of the [{(F3C)3CO}Al{4-MePhCHO}5]2+ dication.
• Demonstration of deoxygenative elimination of aldehyde ligands upon reaction with Et3SiH.
• Instantaneous promotion of alkene hydrosilylation by the unveiled reactive aluminum center.

Conclusions:

• The perfluoro-tert-butoxyaluminum dication represents a unique Lewis acidic species.
• The coordinated aldehydes serve as protecting groups, enabling the isolation of a reactive aluminum intermediate.
• This system offers a novel pathway for generating active aluminum catalysts for hydrosilylation.