biostudies-literatureRoy PEngineering and Physical Sciences Research Council253-259https://www.ebi.ac.uk/biostudies/studies/S-EPMC9841557biostudies-literatureUnknown14(1)Symmetry breaking charge separation (SBCS) is central to photochemical energy conversion. The widely studied 9,9-bianthryl (9,9'BA) is the prototype, but the role of bianthryl structure is hardly investigated. Here we investigate excited state structural dynamics in a bianthryl of reduced symmetry, 1,9-bianthryl (1,9'BA), through ultrafast electronic and vibrational spectroscopy. Resonance selective Raman in polar solvents reveals a Franck-Condon state mode that disappears concomitant with the rise of ring breathing modes of radical species. Solvent-dependent dynamics show that CS is driven by solvent orientational motion, as in 9,9'BA. In nonpolar solvents the excited state undergoes multistep structural relaxation, including subpicosecond Franck-Condon state decay and biexponential diffuThe journal of physical chemistry lettersSolvent Tuning Excited State Structural Dynamics in a Novel Bianthryl.PMC9841557EP/R042357/1EP/J009148/1Meech SRCammidge ANRoy PAl-Kahtani FfalseSolvent Tuning Excited State Structural Dynamics in a Novel Bianthryl.Symmetry breaking charge separation (SBCS) is central to photochemical energy conversion. The widely studied 9,9-bianthryl (9,9'BA) is the prototype, but the role of bianthryl structure is hardly investigated. Here we investigate excited state structural dynamics in a bianthryl of reduced symmetry, 1,9-bianthryl (1,9'BA), through ultrafast electronic and vibrational spectroscopy. Resonance selective Raman in polar solvents reveals a Franck-Condon state mode that disappears concomitant with the rise of ring breathing modes of radical species. Solvent-dependent dynamics show that CS is driven by solvent orientational motion, as in 9,9'BA. In nonpolar solvents the excited state undergoes multistep structural relaxation, including subpicosecond Franck-Condon state decay and biexponential diffu2023-01-01T00:00:00Z2023 Jan2025-04-26T09:54:08.14Z2025-04-06T13:12:18.851ZS-EPMC98415573659492510.1021/acs.jpclett.2c03469