Cyclometalated gold(iii) complexes: noticeable differences between (N,C) and (P,C) ligands in migratory insertion

Area of Science:

• Organometallic Chemistry
• Gold Catalysis
• Ligand Design

Background:

• Gold(III) complexes are increasingly important in opto-electronics, therapy, and catalysis.
• Understanding factors controlling gold(III) reactivity, especially ligand influence, is crucial but limited.

Purpose of the Study:

• To comprehensively study the reactivity of a cationic (N,C) gold(III) complex with ethylene.
• To compare its reactivity with a related (P,C) gold(III) complex.
• To elucidate the role of ancillary ligands in gold(III) reactivity.

Main Methods:

• Experimental investigation of cationic (N,C) gold(III) complex reactivity towards ethylene.
• Comparison with a related (P,C) gold(III) complex.
• Computational analysis of reaction energy profiles.

Main Results:

• Selective formation of a stable cationic gold(III) complex (5A) via double ethylene insertion.
• The (N,C) complex exhibited distinct reactivity, avoiding β-H elimination and rearrangement seen with the (P,C) complex.
• Electronic asymmetry of the (N,C) ligand significantly altered reaction pathways compared to the (P,C) ligand.

Conclusions:

• Ancillary ligand electronic properties critically influence gold(III) reactivity and reaction outcomes.
• The electronic dissymmetry of the (N,C) ligand impacts the competition between migratory insertion and β-H elimination.
• Findings provide key insights for developing advanced Au(III) and Au(I)/Au(III) catalysis.