Tricarbonyl rhenium(i) tetrazolato and N-heterocyclic carbene complexes: versatile visible-light-mediated photoredox catalysts

We have investigated the capacity of a range of structurally-diverse, photoactive rhenium(I) tricarbonyl complexes featuring either tetrazolato or N-heterocyclic carbene (NHC) ligands to facilitate fundamental classes of visible-light-mediated photoredox-catalysed reactions. In this study, we demonstrate that these systems mediate representative atom-transfer radical addition, hydrodehalogenation, and α-amino C–H functionalisation reactions. These rhenium(I) complexes provide greater or at least comparable reactivity to the prototypical photoredox catalyst [Ru(bpy)3]2+ in many cases.