Tandem photoelectrochemical and photoredox catalysis for efficient and selective aryl halides functionalization by solar energy

Summary Solar energy conversion is the most important chemical transformation for green and sustainable society. Represented herein is a coupled catalytic strategy for efficient, selective, and energy-saving organic transformations, i.e., a coupled photoelectrochemical/photoredox setting with Sb2(S,Se)3 as a photocathode and N,N-bis(2,6-diisopropylphenyl)perylene-3,4,9,10-bis(dicarboximide) (PDI) as a photocatalyst shows full-solar-spectrum response extending visible and near-infrared (Vis-NIR) light to 1,060 nm. At −0.84 V versus SCE, the Vis-NIR photoexcited electron from Sb2(S,Se)3 reduces PDI to PDI⋅−. Then, the second photoexcitation by Vis light creates higher reducing PDI⋅−∗ (−1.86 V versus SCE) for reduction of unactivated aryl halides. The resultant aryl radicals are applied for C-C, C-P, and C-B bond-forming reactions with excellent chemoselectivity and efficacy under external sacrificial agent-free conditions. This strategy not only utilizes full solar spectrum and surmounts the limited light absorption of photocatalysis, but also overcomes the high biased potential issue in electrocatalysis.