Stability and Reactivity of Aromatic Radical Anions in Solution with Relevance to Birch Reduction

0584308 - ÚFCH JH 2025 RIV US eng J - Journal Article
Nemirovich, T. - Young, B. - Březina, K. - Mason, P. E. - Seidel, R. - Stemer, D. - Winter, B. - Jungwirth, P. - Bradforth, S. E. - Schewe, Hanns Christian
Stability and Reactivity of Aromatic Radical Anions in Solution with Relevance to Birch Reduction.
Journal of the American Chemical Society. Roč. 146, č. 12 (2024), s. 8043-8057. ISSN 0002-7863. E-ISSN 1520-5126
R&D Projects: GA ČR GA24-10982S
Institutional support: RVO:61388955
Keywords : generalized gradient approximation * state perturbation-theory * photoelectron-spectroscopy * electronic-structure * vibrational-spectra * raman-spectra * hartree-fock * liquid water * naphthalene * benzene
OECD category: Physical chemistry
Impact factor: 15, year: 2022
Method of publishing: Open access

We investigate the electronic structure of aromatic radical anions in the solution phase employing a combination of liquid-jet (LJ) photoelectron (PE) spectroscopy measurements and electronic structure calculations. By using recently developed protocols, we accurately determine the vertical ionization energies of valence electrons of both the solvent and the solute molecules. In particular, we first characterize the pure solvent of tetrahydrofuran (THF) by LJ-PE measurements in conjunction with ab initio molecular dynamics simulations and G(0)W(0) calculations. Next, we determine the electronic structure of neutral naphthalene (Np) and benzophenone (Bp) as well as their radical anion counterparts Np- and Bp(-) in THF. Wherever feasible, we performed orbital assignments of the measured PE features of the aromatic radical anions, with comparisons to UV-vis absorption spectra of the corresponding neutral molecules being instrumental in rationalizing the assignments. Analysis of the electronic structure differences between the neutral species and their anionic counterparts provides understanding of the primarily electrostatic stabilization of the radical anions in solution. Finally, we obtain a very good agreement of the reduction potentials extracted from the present LJ-PES measurements of Np- and Bp(-) in THF with previous electrochemical data from cyclic voltammetry measurements. In this context, we discuss how the choice of solvent holds significant implications for optimizing conditions for the Birch reduction process, wherein aromatic radical anions play crucial roles as reactive intermediates.
Permanent Link: https://hdl.handle.net/11104/0352239