Solvent-Controlled Product Branching in Riboflavin Uncovered by Time-Resolved Infrared and Transient Absorption Spectroscopy.
- 1School of Chemistry, University of Bristol, Cantock's Close, BristolBS8 1TS, U.K.
- 2School of Biochemistry, University of Bristol, University Walk, BristolBS8 1TD, U.K.
Abstract
Riboflavin (vitamin B2) is an important visible chromophore in flavoproteins and a popular photosensitizer in organic photocatalysis. Despite its importance, a complete understanding of riboflavin's full photocycle remains undetermined, specifically the factors that govern the relative yields of its singlet and triplet excited states─both playing important roles in electron transfer chemistry. A combination of transient absorption spectroscopy and time-resolved infrared spectroscopy is used to address this problem, tracking the photoexcited states of riboflavin over 9 decades of time under the same experimental conditions. These studies reveal that the triplet quantum yield increases by a factor of 2.7 by merely changing the solvent from DMSO to H2O. Electronic structure calculations show that this enhancement is not likely to originate from a change in the associated singlet and triplet state potential surfaces. Instead, we discern solvent-dependent branching, with more efficient internal conversion in DMSO, likely mediated by its stronger hydrogen bonding acceptor character than water. This strong modulation shows that the triplet branching, and thus the reservoir of long-lived states required for electron transfer reactions, can be carefully tuned by the immediate environment of the flavin chromophore.
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BibTeX
@article{liu2026solventcontrolled,
title = {{Solvent-Controlled Product Branching in Riboflavin Uncovered by Time-Resolved Infrared and Transient Absorption Spectroscopy.}},
author = {Meiyue Liu and Juno Underhill and Jacob F Jones and Aditya G Rao and Caleb J C Jordan and Somnath Kashid and James A Smith and J L Ross Anderson and Adrian J Mulholland and Basile F E Curchod and Thomas A A Oliver},
journal = {The journal of physical chemistry letters},
year = {2026},
month = sep,
doi = {10.1021/acs.jpclett.6c02005},
url = {https://europepmc.org/article/MED/42917853},
note = {CC BY},
}
RIS
TY - JOUR
TI - Solvent-Controlled Product Branching in Riboflavin Uncovered by Time-Resolved Infrared and Transient Absorption Spectroscopy.
AU - Meiyue Liu
AU - Juno Underhill
AU - Jacob F Jones
AU - Aditya G Rao
AU - Caleb J C Jordan
AU - Somnath Kashid
AU - James A Smith
AU - J L Ross Anderson
AU - Adrian J Mulholland
AU - Basile F E Curchod
AU - Thomas A A Oliver
PY - 2026
DA - 2026/09/01
JO - The journal of physical chemistry letters
DO - 10.1021/acs.jpclett.6c02005
UR - https://europepmc.org/article/MED/42917853
AB - Riboflavin (vitamin B2) is an important visible chromophore in flavoproteins and a popular photosensitizer in organic photocatalysis. Despite its importance, a complete understanding of riboflavin's full photocycle remains undetermined, specifically the factors that govern the relative yields of its singlet and triplet excited states─both playing important roles in electron transfer chemistry. A combination of transient absorption spectroscopy and time-resolved infrared spectroscopy is used to address this problem, tracking the photoexcited states of riboflavin over 9 decades of time under the same experimental conditions. These studies reveal that the triplet quantum yield increases by a factor of 2.7 by merely changing the solvent from DMSO to H2O. Electronic structure calculations show that this enhancement is not likely to originate from a change in the associated singlet and triplet state potential surfaces. Instead, we discern solvent-dependent branching, with more efficient internal conversion in DMSO, likely mediated by its stronger hydrogen bonding acceptor character than water. This strong modulation shows that the triplet branching, and thus the reservoir of long-lived states required for electron transfer reactions, can be carefully tuned by the immediate environment of the flavin chromophore.
SN - 1948-7185
ER -