Following in Emil Fischer's footsteps: a site-selective probe of glucose acid-base chemistry

  • Liquid-jet photoelectron spectroscopy was applied to determine the first acid dissociation constant (pKa) of aqueous-phase glucose while simultaneously identifying the spectroscopic signature of the respective deprotonation site. Valence spectra from solutions at pH values below and above the first pKa reveal a change in glucose’s lowest ionization energy upon the deprotonation of neutral glucose and the subsequent emergence of its anionic counterpart. Site-specific insights into the solution-pH-dependent molecular structure changes are also shown to be accessible via C 1s photoelectron spectroscopy. The spectra reveal a considerably lower C 1s binding energy of the carbon site associated with the deprotonated hydroxyl group. The occurrence of photoelectron spectral fingerprints of cyclic and linear glucose prior to and upon deprotonation are also discussed. The experimental data are interpreted with the aid of electronic structure calculations. Our findings highlight the potential of liquid-jet photoelectron spectroscopy to act as a site-selective probe of the molecular structures that underpin the acid–base chemistry of polyprotic systems with relevance to environmental chemistry and biochemistry.

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Author:Sebastian Malerz, Karen Denise Mudryk, Lukáš Tomaník, Dominik Stemer, Uwe Hergenhahn, Tillmann Buttersack, Florian Trinter, Robert Seidel, Wilson Quevedo, Claudia Goy, Iain Wilkinson, Stephan ThürmerORCiD, Petr Slavíček, Bernd Winter
Parent Title (English):The journal of physical chemistry
Place of publication:Washington, DC
Document Type:Article
Date of Publication (online):2021/07/30
Date of first Publication:2021/07/30
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2022/05/18
Page Number:12
First Page:6881
Last Page:6892
L.T. and P.S. acknowledge support by the Czech Science Foundation, project no. 21-26601X (EXPRO). L.T. acknowledges Specific University Research grant no. A2_FCHI_2021_028. F.T. and B.W. acknowledge support from the MaxWater initiative of the Max-Planck-Gesellschaft. B.W. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and investigation programme (grant agreement no. 883759). R.S. and W.Q. acknowledge funding from the German Research Foundation through an Emmy-Noether grant (SE 2253/3-1). S.T. acknowledges support from the JSPS KAKENHI grant no. JP20K15229.
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0