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oai:figshare.com:article/33428340 2026-10-01T17:33:23Z category_1 category_4 category_146 category_915 category_7 category_873 category_39 category_45 category_64 portal_63 item_type_6 month_year_10_2026

Photophysics of AngelicinThe Simplest Angular Furocoumarin Michelle P. Rademacher (24704316) Jennifer Kremper (24704319) A. Theresa Ott (24704322) Jan Meisner (1372176) Oliver Weingart (1278591) Peter Gilch (1317462) Biophysics Biochemistry Space Science Physical Sciences not elsewhere classified Medicine Chemical Sciences not elsewhere classified Ecology Sociology Cancer ∼ 1 ns simplest angular furocoumarin multireference configuration interaction form interstrand cross electronic excitation energies density functional theory photobiological behavior distinct 1 </ sub relevant excited states state behavior transient opening tentatively ascribed strongly affects solvation effects resolved spectroscopy quantum mechanical pyrone ring psoralens ). protic solvents obtained using molecular mechanical linear analogues explicitly account energetic upshifts aprotic solvents angelicin  Angelicin (ANG) is the simplest angular furocoumarin. It undergoes photoinduced DNA monoadduct formation and does not form interstrand cross-links, resulting in photobiological behavior distinct from that of its linear analogues (psoralens). Here, the photophysics of ANG in the absence of DNA was investigated by steady-state and time-resolved spectroscopy. The nature of the solvent (water, acetonitrile, tetrahydrofuran, toluene, and cyclohexane) strongly affects the excited-state behavior. In water, the first excited singlet state S₁ has a lifetime of ∼1 ns. Its decay is accompanied by the population of the triplet state. In contrast, in all aprotic solvents, the excited singlet state persists only for a few picoseconds and relaxes to the ground state without detectable triplet formation. Quantum mechanical/molecular mechanical (QM/MM) computations were used to explicitly account for solvation effects. Electronic excitation energies were obtained using a combination of density functional theory and multireference configuration interaction (DFT/MRCI) calculations, revealing that all relevant excited states are of ππ* character. Thus, the solvent effects are not due to energetic upshifts of nπ* states in protic solvents. The rapid S₁ decay in aprotic solvents is tentatively ascribed to a transient opening of the α-pyrone ring. 2026-09-17T00:00:00Z Text Journal contribution 10.1021/acs.jpcb.6c04098.s001 https://figshare.com/articles/journal_contribution/Photophysics_of_Angelicin_The_Simplest_Angular_Furocoumarin/33428340 CC BY-NC 4.0