Anionic Derivatives of Perfluorinated Trimethylgold

Area of Science:

• Organometallic Chemistry
• Fluorine Chemistry
• Photochemistry

Background:

• Organogold compounds are valuable synthetic intermediates.
• Perfluorinated alkyl groups significantly alter chemical properties.
• Understanding the stability of organogold(III) species is crucial for their application.

Purpose of the Study:

• To synthesize and characterize a novel organogold(III) complex with a perfluorinated (CF3)3Au fragment.
• To investigate the photochemical reactivity of a homoleptic gold(I) precursor.
• To compare the stability and electronic properties of the perfluorinated gold fragment with its non-fluorinated analog.

Main Methods:

• Photoinduced oxidative addition of trifluoromethyl iodide (CF3I) to [PPh4][CF3AuCF3].
• Density Functional Theory (DFT) calculations to analyze electronic structure and reaction barriers.
• Isolation and characterization of a series of anionic [PPh4][(CF3)3AuX] complexes (X=F, Cl, Br, I, CN).

Main Results:

• Successful synthesis of the organogold(III) derivative [PPh4][(CF3)3AuI] under mild, photoinduced conditions.
• DFT analysis revealed a significantly higher energy barrier for reductive elimination in the (CF3)3Au fragment compared to (CH3)3Au, explaining its enhanced stability.
• Isolation and characterization of a complete series of anionic gold(III) complexes, [PPh4][(CF3)3AuX], demonstrating stabilization by halide and cyanide ligands.

Conclusions:

• The perfluorinated (CF3)3Au fragment exhibits remarkable stability, attributed to the high energy barrier for reductive elimination.
• This study provides convenient access to the chemistry of the (CF3)3Au moiety, opening avenues for new organogold chemistry.
• The unsaturated, 14-electron (CF3)3Au species can be effectively stabilized by anionic ligands.