Copper Photosensitizers Containing P^N Ligands and Their Influence on Photoactivity and Stability

Driven by the intention to improve classic heteroleptic copper photosensitizers two novel Cu(I) complexes applying a hetero‐bidentate P^N ligand were prepared. A combined photophysical, electrochemical, and theoretical study gives insights into structure–activity relationships and revealed an increased absorptivity. Both complexes were tested for the light‐driven production of H2. The more the better: Conventional diphosphine P^P ligands were replaced by a heterobidentate P^N ligand in order to enhance stability and absorptivity of the resulting copper photosensitizers. A combined photophysical, electrochemical, and theoretical study gives insights into structure–activity relationships and explains the photocatalytic activity.