Impact of Solvent Reorganization on Disulfide Bond Cleavage in Hydrated Electron Clusters

Hydrated electron, e−(aq) is a powerful reducing agent in organic synthesis, atmospheric and radiation chemistry with noteworthy biological implications. Its formation and properties have sparked debate among scientists, yet with few insights into its reactions in solvents. To date, reaction mechanism involving e−(aq) remains as an unsolved puzzle. Given its intrinsic structural variability, interaction of e−(aq) with vicinal chemical environment likely depends on its solvation structure and interplay with reorganization of water molecules. Investigating the solvent reorganization associated with a charge transfer from e−(aq) to neighboring chemical species offers valuable insights into its underlying reaction mechanism.

Methods
Reaction dynamics of a chemical model comprising a dimethyl disulfide, the prototypical molecule containing a S―S bond, and a hydrated electron cluster with six water molecules, [CH3SSCH3(H2O)6•–], at 100 K (comparable with the temperature in a previous FT-ICR mass spectrometric study) has been examined using density functional theory based molecular dynamics (DFT-MD) simulations performed with the CP2K Quickstep module. The revPBE functional with restricted open-shell formalism and a triple-ζ basis set with two polarization functions were used. Reaction energy profile was constructed using constraint DFT-MD simulations.

Novel Aspect
Importance and details of solvent reorganization and its influence toward reaction dynamics of hydrated electron has been theoretically revealed.