2026-08-27 パシフィック・ノースウェスト国立研究所（PNNL）
A combination of ultrafast X-ray and optical methods helped resolve transient intermediates along a proton-coupled electron transfer pathway. (Image by Jeff London | Pacific Northwest National Laboratory)
＜関連情報＞
- https://www.pnnl.gov/publications/revealing-how-electronic-structure-and-solvent-reorganize-during-proton-coupled
- https://www.nature.com/articles/s41467-026-75943-4
超高速X線によって捉えられた、プロトン共役電子移動における電子および溶媒の再編成 Electronic and solvent reorganization in proton-coupled electron transfer captured by ultrafast X-rays
Abdullah Kahraman,Michael Sachs,Soumen Ghosh,Benjamin I. Poulter,Estefanía Sucre-Rosales,Elizabeth S. Ryland,Douglas Garratt,Sumana L. Raj,Natalia Powers-Riggs,Subhradip Kundu,Christina Y. Hampton,David J. Hoffman,Giacomo Coslovich,Georgi L. Dakovski,Patrick L. Kramer,Matthieu Chollet,Roberto Alonso-Mori,Tim B. van Driel,Sang-Jun Lee,Kristjan Kunnus,Amy A. Cordones,Robert W. Schoenlein,Eric Vauthey,Amity Andersen,… Elisa Biasin
Nature Communication Published:26 August 2026
DOI:https://doi.org/10.1038/s41467-026-75943-4
Abstract
Proton-coupled electron transfer (PCET) is foundational to catalysis, bioenergetics, and energy conversion, yet directly observing the interplay between electronic redistribution, protonation, and solvent reorganization remains challenging. We combine femtosecond optical spectroscopy, ultrafast N K-edge X-ray absorption spectroscopy, and time-resolved X-ray solution scattering to capture the steps of a sequential PCET reaction in water with atomic-site specificity. Using a ruthenium polypyridyl model complex, we resolve the electron redistribution upon photoinduced metal-to-ligand charge transfer and subsequent ( ~ 460 ps) protonation at a ligand nitrogen, as well as the concomitant rearrangement of the first-solvation-shell. Combined with advanced electronic structure and molecular dynamics simulations, our measurements reveal a marked localization of the excited-state electron density at the protonated N site, together with a switch from N···HO to NH···O hydrogen-bonds. These results establish a multimodal X-ray framework for mechanistic insight into PCET and its control in catalysis, artificial photosynthesis, and biological energy flow.
