Roseanne J Sension, Taylor P McClain, Ryan M Lamb, Roberto Alonso-Mori, Frederico Alves Lima, Fernando Ardana-Lamas, Mykola Biednov, Matthieu Chollet, Taewon Chung, Aniruddha Deb, Paul A Dewan, Leland B Gee, Joel Huang Ze En, Yifeng Jiang, Dmitry Khakhulin, Jianhao Li, Lindsay B Michocki, Nicholas A Miller, Florian Otte, Yohei Uemura, Tim B van Driel, James E Penner-Hahn
Femtosecond time-resolved X-ray absorption (XANES) at the Co K-edge, X-ray emission (XES) in the Co Kβ and valence-to-core regions, and broadband UV-vis transient absorption are combined to probe the femtosecond to picosecond sequential atomic and electronic dynamics following photoexcitation of two vitamin B12 compounds, hydroxocobalamin and aquocobalamin. Polarized XANES difference spectra allow identification of sequential structural evolution involving first the equatorial and then the axial ligands, with the latter showing rapid coherent bond elongation to the outer turning point of the excited state potential followed by recoil to a relaxed excited state structure...
June 16, 2023: Journal of the American Chemical Society