Natural Sunlight-Driven Activation of Inert Aryl Halides Using Plasmonic Cu@CdS with Polysulfide Active Sites

Visible light photoredox catalysis has become a rapidly emerging area owing to its potential of using sunlight to tame previously hard-to-harness radicals for organic synthesis. At present, such a blueprint faces a significant challenge, namely how to accomplish thermodynamically demanding reactions with sunlight encompassing a wide range of low-energy photons. Here, we report a new reaction framework to overcome this bottleneck through decoupling the thermodynamic limits of photoreduction from photoexcitation. This is fulfilled based on the construction of a heterogeneous photocatalyst Cu@CdS possessing in situ-formed surficial polysulfide species (including S 3 •− and S 4 2− ), which can efficiently harvest solar energy via plasmonic absorption of Cu while manifest sufficient redox potential for activating inert aryl bromides/chlorides enacted by excited polysulfides. We demonstrate that this designed material composes a potent photoredox catalyst for efficient aryl cross-coupling, borylation, hydrogenation, as well as Birch-type dearomatization reactions, with good recyclability and stability. In particular, when exclusively using natural sunlight as an energy source, the product yield can still reach up to 90%. Our findings introduce a straightforward yet viable way to progress toward the century-long dream of leveraging natural sunlight to produce structurally complex organic molecules, just like plants on Earth. Graphical Chemists have long aspired to construct complex organic compounds the way that plants do by harnessing natural sunlight as an energy source. This study presents an advancement toward this goal via synergistic exploitation of the plasmonic absorption of Cu and the unique redox potentials of excited polysulfide species (S 3 •− and S 4 2− ) on semiconductor surfaces to decouple the thermodynamic limits of photoreduction from photoexcitation.