Tuning the Photochemistry of Entatic State Model Systems

The entatic state model system, the copper guanidinoquinoline complex pair [Cu(DMEGqu) 2 ] +/2+ , was herein studied regarding its photo‐dynamics upon excitation. The photo‐induced excited states of the copper(I) complex were investigated with time‐resolved infrared and UV/Vis absorption spectroscopy, yielding the excited states’ time constants upon metal‐to‐ligand charge transfer. Additional density functional theory calculations yield insights into the electronic structures of these excited states. The combined theoretical and experimental approach was used to construct the schematic reaction pathway of the excited states of [Cu(DMEGqu) 2 ]PF 6 . Further, using a previous study of an entatic state model complex with a different guanidine moiety, [Cu(TMGqu) 2 ]PF 6 , the substituents’ effects on the complex cation's photo‐dynamics were evaluated. The comparison shows that the less bulky and more rigid DMEG moiety measurably affects the charge transfer dynamics, underscoring the entatic state model as a potential tool for controlling copper photochemistry.