Proton-Coupled Electron Transfer at a [Co-OHx]z Unit in Aqueous Media: Evidence for a Concerted Mechanism

Authors

Derek J. Wasylenko, University of Calgary
Heidi M. Tatlock, Marquette University
Luvdeep S. Bhandari, University of Calgary
James R. Gardinier, Marquette UniversityFollow
Curtis P. Berlinguette, University of Calgary

Document Type

Article

Publication Date

2-2013

Source Publication

Chemical Science

Source ISSN

2041-6520

Abstract

The proton-coupled electron transfer (PCET) chemistry associated with the [Co-OH]²⁺/[Co-OH₂]²⁺ redox couple for [Co(PY5)(OH₂)]²⁺ (1; PY5 = 2,6-(bis(bis-2-pyridyl)-methoxymethane)-pyridine) and [Co^II(pz₄depy)(OH₂)]²⁺ (2; pz₄depy = 2,6-bis(1,1-di(1H-pyrazol-1-yl)ethyl)pyridine) is reported. It is found that the couple is acutely sensitive to the geometry of the axially ligated group in addition to the electronic-donating/-withdrawing character of the ligand. Interrogation of the electron-transfer kinetics by electrochemical methods also shows for the first time that the interconversion of [Co^III-OH]²⁺ and [Co^II-OH₂]²⁺ proceeds through a concerted pathway in favour of energetically unfavourable stepwise electron-transfer or proton-transfer reaction steps.

Comments

Accepted Version. Chemical Science, Vol. 4, No. 2 (February 2013): 734-738. DOI. © 2013 Royal Society of Chemistry. Used with permission.

Recommended Citation

Wasylenko, Derek J.; Tatlock, Heidi M.; Bhandari, Luvdeep S.; Gardinier, James R.; and Berlinguette, Curtis P., "Proton-Coupled Electron Transfer at a [Co-OHx]z Unit in Aqueous Media: Evidence for a Concerted Mechanism" (2013). Chemistry Faculty Research and Publications. 251.
https://epublications.marquette.edu/chem_fac/251