Complex kinetics of ion solvation in confinement and in bulk *

Traditional pictures of solution phase chemistry and biology treat the surrounding solvent as a spectator. However, in recent years, it has been shown that the solvent can be a key player in condensed phase chemical dynamics. In this talk, I will discuss the non-trivial role of the solvent in two fundamental chemical reactions involving ions, electron transfer and solvent exchange. These processes play important roles in energy conversion and storage technologies, geochemistry, and biophysics. I will first discuss ion solvation dynamics surrounding electron transfer reactions in solutions confined within layered transition metal oxide minerals, with an emphasis on guiding principles for catalysis. The interplay between confinement and ion solvation leads to unique structures and dynamics of water molecules that enhance electron transfer rates. This enhancement is explained with an extension of the XY model, creating an analogy to magnetic materials. I will also discuss the complex, facilitated dynamics of water exchange around ions. In particular, the extreme sensitivity of exchange rates to perturbations in the chemistry of an ionic solute is not well understood. By borrowing concepts from the physics of glassy systems, I will demonstrate how the scaling of exchange rates with ion-water interaction strength can be predicted with the help of kinetically-constrained lattice models.