Document Type
Article
Date of Original Version
2023
Department
Civil and Environmental Engineering
Abstract
Hypervalent iron intermediates have been invoked in the catalytic cycles of many metalloproteins, and thus it is crucial to understand how the coupling between such species and their environment can impact their chemical and physical properties in such contexts. In this 2 work, we take advantage of the solvent kinetic isotope effect (SKIE) to gain insight into the nonradiative deactivation of electronic excited states of the aqueous ferrate(VI) ion. We observe an exceptionally large SKIE of 9.7 for the nanosecond-scale relaxation of the lowest energy triplet ligand field state to the ground state. Proton inventory studies demonstrate that a single solvent O-H bond is coupled to the ion during deactivation, likely due to the sparse vibrational structure of ferrate(VI). Such a mechanism is consistent with that reported for the deactivation of f-f excited states of aqueous trivalent lanthanides, which exhibit comparably large SKIE values. This phenomenon is ascribed entirely to dissipation of energy into a higher overtone of a solvent acceptor mode, as any impact on the apparent relaxation rate due to a change in solvent viscosity is negligible.
Publication Title, e.g., Journal
The Journal of Physical Chemistry A
Volume
127
Issue
49
Citation/Publisher Attribution
Antolini, Cali, Danielle J. Jacoby, Sophia M. Tiano, Christopher J. Otolski, Gilles Doumy, Anne M. March, Donald A. Walko, Joseph E. Goodwill, and Dugan Hayes. "A Ten-Fold Solvent Kinetic Isotope Effect for the Nonradiative Relaxation of the Aqueous Ferrate(VI) Ion." The Journal of Physical Chemistry A 127, 49 (2023). doi: 10.1021/acs.jpca.3c06042.
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