Work

Fast singlet excited-state deactivation pathway of flavin with a trimethoxyphenyl derivative

Year: 2024

Type: article

Abstract: Incorporation of the trimethoxyphenyl group at position 7 of flavin can drastically change the photophysical properties of flavin. We show unique fast singlet 1 (π,π*) excited state deactivation pathway through nonadiabatic transition to the 1 (n,π*) excited- state, and subsequent deactivation to the ground electronic state (S 0 ), closing the photocycle. This mechanism explains the exceptionally weak fluorescence and the short excited–state lifetime for the flavin trimethoxyphenyl derivative and the lack of excited triplet T 1 state formation. Full recovery of flavin in its ground state takes place within a 15 ps time window after photoexcitation in a polar solvent such as acetonitrile. According to quantum chemical calculations, the C (2) -O distance elongates by 0.16 Å in the 1 (n,π*) state, with respect to the ground state. Intermediate–state structures are predicted by theoretical ab initio calculations and their dynamics are investigated using broadband vis-NIR time-resolved transient absorption and fluorescence up-conversion techniques.

Source: Scientific Reports

DOI: 10.1038/s41598-024-75239-x