Control of Charge Separation and Recombination Processes by Selection and Connectivity of Bridges in Donor–Chiral Bridge–Acceptor (D–χ–A) Molecules

Photogenerated spin-correlated radical pairs (SCRPs) in donor-bridge-acceptor (D-B-A) systems represent a promising platform for developing molecular quantum technologies using their sensitivity to magnetic and electric fields. For SCRPs to be sensitive to weak magnetic fields, they need to have sufficiently long lifetimes for efficient spin evolutions. We recently identified that H8-BINOL, a partially reduced form of BINOL, can act as a bridge to produce SCRPs with lifetimes of >100 ns, enabling a large magnetic modulation of molecular emission in solution at room temperature (J. Am. Chem. Soc. 2025, 147, 13, 11062). The present study explores the role of chiral BINOL as a bridging segment in D-χ-A molecules, where boron dipyrromethene (BODIPY) and triarylamine (TAA) derivatives act as acceptor and donors, respectively. We systematically varied both the connectivity of the BINOL bridge and the BINOL scaffold itself, finding that these structural and electronic changes significantly influence the charge-transfer dynamics. These findings highlight the potential of BINOL-based bridges to facilitate spin-selective phenomena and controlled charge transfer processes. The insights gained from this work contribute to the development of advanced chiral molecular architectures for quantum sensing and spintronics.