Ultrafast Intrinsic Electron Transfer Dynamics in a Sterically Preorganized Corrole-Perylene Bisimide Dyad

Rigid donor-acceptor (D-A) dyads comprising a directly linked doubly N-methylated corrole (COR) donor and a perylene bisimide (PBI) acceptor were synthesized via an aza-annulation strategy based on a modified Pictet-Spengler reaction. Core N-methylation induces pronounced nonplanar distortion, enforcing close spatial proximity between donor and acceptor within a sterically preorganized framework. The resulting architecture enables efficient through-space electronic communication without the need for intervening π-bridges or conformational reorganization. Despite the absence of strong ground-state electronic delocalization, fluorescence quenching, and femtosecond transient absorption spectroscopic studies reveal ultrafast, solvent-dependent photoinduced electron transfer from COR to PBI. Particularly, charge separation persists for the COR-PBI-PS dyad even in highly viscous media, indicating that large-amplitude structural relaxation is not the dominant driving force, instead, electron transfer is intrinsically driven by the preorganized through-space D-A arrangement. These findings establish rigid COR-PBI dyads as effective platforms for ultrafast charge separation, independent of conformational gating.