Gold(I) Fluorohalides: Theory and Experiment

Area of Science:

• Organometallic Chemistry
• Fluorine Chemistry
• Computational Chemistry

Background:

• Anionic trifluoromethylgold(I) complexes, [CF3AuX]−, were synthesized and isolated as tetraphenylphosphonium ([PPh4]+) salts.
• These compounds exhibit unique reactivity under thermal conditions.

Purpose of the Study:

• To investigate the thermal decomposition pathway of anionic trifluoromethylgold(I) derivatives.
• To characterize the resulting gold(I) fluorohalide complexes.
• To explore the mechanism of difluorocarbene extrusion and insertion reactions involving gold.

Main Methods:

• Synthesis and isolation of [CF3AuX]− ([PPh4]+ salts).
• Gas-phase thermal decomposition studies.
• Tandem mass spectrometry (MS2) for detection and analysis of reaction products.
• Density Functional Theory (DFT) calculations for property analysis and mechanistic insights.

Main Results:

• Thermally induced extrusion of difluorocarbene (CF2) from [CF3AuX]− was observed in the gas phase.
• Formation of triatomic mixed gold(I) fluorohalide complexes, [F-Au-X]− (X=Cl, Br, I), was confirmed by MS2.
• DFT analysis provided insights into the electronic structure and properties of the [F-Au-X]− species.

Conclusions:

• The CF2 extrusion mechanism from the Au-CF3 moiety serves as a model for CF2 insertion into the Au-F bond.
• The principle of microreversibility connects the extrusion and insertion reaction pathways.
• This research expands the understanding of gold-CF2 chemistry and provides a route to novel gold(I) fluorohalide complexes.