Photoredox catalysis has become an extremely valuable process in organic synthesis. The most popular photocatalysts are based on ruthenium(II) and iridium(III) complexes such as [Ru(bpy)3]2+ and fac-Ir(ppy)3. The detracting feature of these catalysts is that the metals are both expensive and toxic.[1,2] Copper(I) complexes present an inexpensive and versatile alternative for use in photoredox catalysis, which has enticing potential for small molecule transformations.
We present the design, computational modelling, synthesis and optoelectronic characterisation of a series of photoactive Cu(I)-NHC complexes, which are designed to negatively shift the excited state oxidation potential and so be better photoreductants. We also show preliminary efforts of their use in a range of photocatalytic organic transformations including C-H activation, C-C bond forming, ATRA and energy transfer reactions.[4,5]
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