Mechanistic studies of water oxidation catalyzed by monomeric Ru complexes

Dmitry E. Polyansky, Jonathan Rochford, Etsuko Fujita, James T. Muckerman, Randolph P. Thummel, Ruifa Zong

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The possible design of an artificial solar fuel production system can be inspired by natural photosynthesis in which light-induced charge separation is coupled to redox reactions driven by molecular catalysts. The water oxidation reaction facilitated by catalysts represents an important and very challenging process required for the successful realization of artificial photosynthetic schemes. Ruthenium based water oxidation catalysts incorporating two metal centers have been known to catalyze water oxidation in the presence of sacrificial electron acceptors or driven by electrode bias according to a four-electron oxidation scheme, however a few intriguing exceptions have been reported where mononuclear Ru complexes can act as catalysts. We have studied the reactivity of mononuclear Ru polypyridyl complexes that are capable of catalytically splitting water in the presence of sacrificial electron acceptors. Product analysis during the course of the water oxidation reaction in the presence of Ce(IV) salts indicates that the integrity of some mononuclear catalysts is compromised as evidenced by carbon dioxide evolution, while others are stable under experimental conditions. The mechanistic details of water oxidation catalysis were derived from the kinetic behavior of reaction intermediates observed during time-resoled pulse radiolysis experiments and pH dependent electrochemical studies. The electronic properties of observed intermediates were analyzed using DFT and TD-DFT methods, and agree well with experimental data. The experimental and theoretical characterization of mononuclear Ru complexes in higher oxidation states points towards a significant radical character of the transient species that plays an important role in the mechanism of the water oxidation reaction.

Original languageEnglish
Title of host publicationAmerican Chemical Society - 238th National Meeting and Exposition, ACS 2009, Abstracts of Scientific Papers
Publication statusPublished - Dec 1 2009
Event238th National Meeting and Exposition of the American Chemical Society, ACS 2009 - Washington, DC, United States
Duration: Aug 16 2009Aug 20 2009

Publication series

NameACS National Meeting Book of Abstracts
ISSN (Print)0065-7727

Other

Other238th National Meeting and Exposition of the American Chemical Society, ACS 2009
CountryUnited States
CityWashington, DC
Period8/16/098/20/09

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ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Cite this

Polyansky, D. E., Rochford, J., Fujita, E., Muckerman, J. T., Thummel, R. P., & Zong, R. (2009). Mechanistic studies of water oxidation catalyzed by monomeric Ru complexes. In American Chemical Society - 238th National Meeting and Exposition, ACS 2009, Abstracts of Scientific Papers (ACS National Meeting Book of Abstracts).