Catechol/o-benzoquinone exchange at gold(iii).

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Catalysis

Background:

• Gold(III) chemistry has advanced significantly, yet gold(III) catecholate complexes are notably scarce.
• Existing research has not fully explored ligand exchange mechanisms in these systems.

Purpose of the Study:

• To investigate the ligand exchange dynamics of P^C-cyclometalated gold(III) complexes.
• To elucidate the mechanism of catecholate displacement by o-benzoquinones at gold(III).

Main Methods:

• Synthesis and full characterization of P^C-cyclometalated gold(III) complexes.
• Experimental observation of catecholate/o-benzoquinone exchange.
• Density Functional Theory (DFT) calculations to model the reaction pathway.

Main Results:

• Serendipitous discovery of an intriguing catechol exchange process at gold(III).
• Electron-rich catecholates are readily displaced by electron-poor o-benzoquinones.
• DFT calculations reveal a novel mechanism involving two consecutive Single Electron Transfer (SET) events, with gold maintaining its +III oxidation state.

Conclusions:

• The observed catechol/o-benzoquinone exchange at gold(III) represents a new pathway for X-type ligand exchange at transition metals.
• This finding expands the understanding of reactivity and ligand substitution in gold(III) coordination chemistry.