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

2024/02/16 by Tatiana Nemirovich, Brandon Young, Kryštof Březina +7 · 1 voice · 8 citations
Chemistry · Physics and Astronomy · #Ab initio #Chemistry #Computational chemistry #Electrochemical Analysis and Applications #Electronic structure #Ion #Molecule #Organic chemistry #Photochemistry #Photochemistry and Electron Transfer Studies #Radical ion #Solvent #Spectroscopy and Quantum Chemical Studies #Tetrahydrofuran #Valence (chemistry)

paper · doi:10.1021/jacs.3c11655

published in Journal of the American Chemical Society 146(12), 8043-8057 (American Chemical Society)

openalex publication_date 2024/02/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

High Resolution Image Download MS PowerPoint Slide 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.

Citations

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• A consistent and accurateab initioparametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
• Effect of the damping function in dispersion corrected density functional theory
• CP2K: An Electronic Structure and Molecular Dynamics Software Package -- Quickstep: Efficient and Accurate Electronic Structure Calculations
• Chemical Redox Agents for Organometallic Chemistry
• Scalable Birch reduction with lithium and ethylenediamine in tetrahydrofuran

Discussions

• 🧫 In search of friendly room temperature solvents for Birch reduction – a team led by Christian Schewe (Pavel Jungwirth Group) and colleagues described Stability and Reactivity of Aromatic Radical An [bsky, 0 points, 0 comments]

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