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Title: Base-enhanced catalytic water oxidation by a carboxylate–bipyridine Ru(II) complex

In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [RuII(bda)(isoq)2] (bda is 2,2'-bipyridine-6,6'-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [RuII(CO2-bpy-CO2$-$)(isoq)2(NCCH3)], as shown by 1H and 13C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, as measured by cyclic voltammetry (CV). In 1.0 M PO43–, the calculated half-time for water oxidation is ~7 μs. In conclusion, the key to the rate accelerations with added bases is direct involvement of the buffer base in either atom–proton transfer (APT) or concerted electron–proton transfer (EPT) pathways.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2]
  1. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry
  3. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemistry and Biochemistry
Publication Date:
OSTI Identifier:
1210509
DOE Contract Number:
SC0001011; CHE-0957215
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America; Journal Volume: 112; Journal Issue: 16
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Energy Frontier Research Centers (EFRC). Center for Solar Fuels (UNC EFRC)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
UNC partners with University of North Carolina (lead); Duke University; University of Florida; Georgia Institute of Technology; University; North Carolina Central University; Research Triangle Institute
Country of Publication:
United States
Language:
English
Subject:
catalysis (homogeneous); catalysis (heterogeneous); solar (photovoltaic); solar (fuels); photosynthesis (natural and artificial); hydrogen and fuel cells; electrodes - solar, charge transport; materials and chemistry by design; synthesis (novel materials); synthesis (self-assembly); Ru polypyridyl complexes; electrocatalysis; solar energy; water oxidation catalysis; water splitting