Gold-Manganese Bimetallic Redox Coupling with Light

The classical Au(I)/Au(III) redox couple chemistry has been limited to constructing C-C and C-X bonds, and thus, the exploration of the elementary reaction of gold redox coupling is very significant to enrich its organometallic features. Herein, we report the first visible-light-mediated, external oxidant-free Au(I)/Au(III) redox couple using commercially available Mn-2(CO)(10) to generate Mn-Au(III)-Mn intermediates for bimetallic redox coupling. A wide range of structurally diverse heterodinuclear and polynuclear L-Au(I)-Mn-L ' complexes (19 examples, up to >99% yields) are readily constructed, providing a robust strategy for the concise construction of Au-Mn complexes under mild reaction conditions. The mechanistic studies together with DFT calculations support the radical oxidative addition of Mn-center dot(CO)(5) to gold and bimetallic reductive elimination mechanisms from highly active Mn-Au(III)-Mn species, representing an important step toward an elementary reaction in gold chemistry research. Furthermore, the resulting Au-Mn complexes exhibit unique catalytic activity, with which divergent reductive coupling of nitroarenes can readily afford azoxybenzenes, azobenzenes, and hydrazobenzenes in moderate to good yields.

Automated summary

In this study, the first visible-light-mediated, external oxidant-free Au(I)/Au(III) redox couple was reported. By using commercially available Mn-2(CO)(10) to generate Mn-Au(III)-Mn intermediates, a wide range of structurally diverse Au-Mn complexes can be readily constructed under mild reaction conditions, representing an important progress in gold chemistry research. The resulting complexes also exhibit unique catalytic activity and can be used for the synthesis of azoxybenzenes, azobenzenes, and hydrazobenzenes in moderate to good yields.