Dataset of "Liquid-Jet Photoemission Spectroscopy as a Structural Tool: Site-Specific Acid-Base Chemistry of Vitamin C"

Liquid-jet photoemission spectroscopy (LJ-PES) directly probes the electronic structure of solutes
and solvents. It also emerges as a novel tool to explore chemical structure in aqueous solutions, yet
the scope of the approach has to be examined. Here, we present a pH-dependent liquid-jet photoelectron
spectroscopic investigation of ascorbic acid (vitamin C). We combine core-level photoelectron
spectroscopy and ab initio calculations, allowing us to site-specifically explore the acid-base chemistry
of the biomolecule. For the first time, we demonstrate the capability of the method to simultaneously
assign two deprotonation sites within the molecule. We show that a large change in chemical shift
appears even for atoms distant several bonds from the chemically modified group. Furthermore, we
present a highly efficient and accurate computational protocol based on a single structure using the
maximum overlap method for modeling core-level photoelectron spectra in aqueous environments.
This work poses a broader question: To what extent can LJ-PES complement established structural
techniques such as nuclear magnetic resonance? Answering this question is highly relevant in view
of the large number of incorrect molecular structures published.