Ultrafast, Non-Productive, Deprotonation of the Excited Flavylium Cation in Delphinidin-3-O-Rutinoside
- 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
Abstract
Anthocyanins are widespread natural pigments responsible for the vibrant colors of fruits and flowers and play key roles in photoprotection. Despite their biological significance, the interplay between excited-state proton transfer (ESPT) and ultrafast relaxation remains poorly understood. Here, we investigate the ultrafast excited-state dynamics of delphinidin-3-O-rutinoside (D3R) in aqueous solution at pH 2—where the protonated flavylium cation dominates—using femtosecond broadband transient absorption spectroscopy. Excitation at 525 nm induces rapid spectral changes on the sub-picosecond timescale connected with sub 50 fs deprotonation in the excited state. Global analysis reveals two dominant processes: a 0.12 ps component assigned to ultrafast proton transfer from the excited flavylium cation to the solvent, forming the electronically excited quinoidal base (QB). This is followed by a 0.47 ps component characterized by strong bleach recovery, representing the primary relaxation pathway back to the ground state of at least 70%. Partial germinal reprotonation occurs upon electronic relaxation to the ground state. A mixture of vibrationally excited D3R and QB results. A characteristic time scale is around 3 ps. Reprotonation of QB occurs on the ps–ns timescale via diffusion-controlled processes. The overall process enables rapid dissipation of excitation energy, providing a mechanistic basis for the photoprotective function of anthocyanins in biological systems.
Related
- The Sec11 C-terminal short helix promotes productive engagement of internal signal sequences with the signal peptidase complex
- Carbonyl Recycling Limits Productive Ethanol Formation during Syngas Conversion on Rh(211): A First-Principles Microkinetic Analysis
- Geometry-Dependent Redistribution of Exocytotic Spike-Shape Populations Revealed by Ultrafast Disk and Nanotip Acetylcholine Biosensors
- Ultrafast Charge Separation Controlled by Aromatic Guests in a Perylene Dimer
- Dielectric sensing of ultrafast reaction-induced phase separation at a model liquid-liquid interface
BibTeX
@article{bartonitz2026ultrafast,
title = {{Ultrafast, Non-Productive, Deprotonation of the Excited Flavylium Cation in Delphinidin-3-O-Rutinoside}},
author = {Florian Bartonitz and J. Luis Pérez Lustres and Karsten Heyne},
journal = {Molecules},
year = {2026},
month = oct,
doi = {10.3390/molecules31203645},
url = {https://www.mdpi.com/1420-3049/31/20/3645},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Ultrafast, Non-Productive, Deprotonation of the Excited Flavylium Cation in Delphinidin-3-O-Rutinoside
AU - Florian Bartonitz
AU - J. Luis Pérez Lustres
AU - Karsten Heyne
PY - 2026
DA - 2026/10/13
JO - Molecules
DO - 10.3390/molecules31203645
UR - https://www.mdpi.com/1420-3049/31/20/3645
AB - Anthocyanins are widespread natural pigments responsible for the vibrant colors of fruits and flowers and play key roles in photoprotection. Despite their biological significance, the interplay between excited-state proton transfer (ESPT) and ultrafast relaxation remains poorly understood. Here, we investigate the ultrafast excited-state dynamics of delphinidin-3-O-rutinoside (D3R) in aqueous solution at pH 2—where the protonated flavylium cation dominates—using femtosecond broadband transient absorption spectroscopy. Excitation at 525 nm induces rapid spectral changes on the sub-picosecond timescale connected with sub 50 fs deprotonation in the excited state. Global analysis reveals two dominant processes: a 0.12 ps component assigned to ultrafast proton transfer from the excited flavylium cation to the solvent, forming the electronically excited quinoidal base (QB). This is followed by a 0.47 ps component characterized by strong bleach recovery, representing the primary relaxation pathway back to the ground state of at least 70%. Partial germinal reprotonation occurs upon electronic relaxation to the ground state. A mixture of vibrationally excited D3R and QB results. A characteristic time scale is around 3 ps. Reprotonation of QB occurs on the ps–ns timescale via diffusion-controlled processes. The overall process enables rapid dissipation of excitation energy, providing a mechanistic basis for the photoprotective function of anthocyanins in biological systems.
SN - 1420-3049
ER -