[Cu(bcp)DPEPhos]+: a Versatile and Efficient Copper-Based Photoredox Catalyst and Photosensitizer

The development of photoredox catalysis has recently enabled the design of remarkably powerful synthetic tools now commonly used in a wide array of chemical transformations, and notably for the generation of radical species under mild, safe and environmentally friendly conditions. This field is largely dominated by ruthenium and iridium complexes, the main alternative to the use of these photocatalysts mostly relying on the use of organic dyes, which poses problems not only in terms of cost - therefore strongly limiting synthetic applications of photocatalysis - but also, more importantly, for the design of new light-mediated transformations. Much less attention has been devoted to the use of copper complexes in photoredox catalysis, despite their strong potential not only as cheaper catalysts but also for the activation of a broader range of substrates. Most copper complexes are indeed known to be poor photocatalysts, mostly due to their short-lived excited states and low redox potentials. Over the last decade, one copper-based copper complex has however emerged as a remarkably efficient and general photoredox catalyst, which is at the core of this Spotlight that highlights its applications as a photosensitizer and its potential.