Redox Reactions with Bimetallic Cooperation

Di-gold(I) species supported or semi-supported by ditopic bridging ligands are legion. Chronicled here are some attractive developments of the last 5 years. 

Energy storage is fundamental to large-scale utilization of the solar resource. Nocera and coworkers have developed redox reactions of dimetal centers that exploit aurophilic interactions and metal-lophilicity more generally. 

Thermal reductive eliminations are faster for di-gold complexes and show evidence for bimetallic cooperation. Moreover, reductive elimination from a dibromide complex is accelerated by buildup or addition of the corresponding product. The authors do not speculate on the microscopic origin of any metal-metal cooperation, but aurophilic assistance is a plausible hypothesis. 

Elemental chlorine and bromine add to the solid gold(I) compounds to yield gold(lll) analogs that are the authors initial photoreactants. This reaction is undone upon light excitation. The energystoring attribute of these trap-free photoreactions is thereby proven. 

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Carbon-heteroatom reductive elimination from dinuclear transition metal complexes, as was proposed by us [96,109] as the product-forming step in Pd-catalyzed C-H acetoxylation and chlorination reactions, is rare. The two formulations of the high-valent, dinuclear Pd intermediate in arylation proposed by Sanford (60 and 61) highlight that reductive elimination from dinuclear Pd structures could, in principle, proceed with either redox chemistry at both metals (bimetallic reductive elimination reductive elimination from 60) or with redox chemistry at a single metal (monometallic redox chemistry reductive elimination from 61). While structures 60 and 61 do not differ in composition, they do differ in their respective potentials for metal-metal redox cooperation to be involved in C-C bond-forming reductive elimination. 

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