Ruthenium Water Oxidation Catalysts based on Pentapyridyl Ligands
| Autor: | Roger Bofill, Roger Alberto, Craig J. Richmond, Cyril Bachmann, Carolina Gimbert-Suriñach, Michael Böhler, Antoni Llobet, Sandra Luber, Mauro Schilling, Fernando Bozoglian, Xavier Sala, Marcos Gil-Sepulcre, Thomas Fox, Bernhard Spingler, Dominik Scherrer |
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| Přispěvatelé: | University of Zurich, Luber, Sandra |
| Rok vydání: | 2017 |
| Předmět: |
10120 Department of Chemistry
2100 General Energy General Chemical Engineering Inorganic chemistry chemistry.chemical_element 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis chemistry.chemical_compound Oxidation state 540 Chemistry Environmental Chemistry General Materials Science Qualitative inorganic analysis 1500 General Chemical Engineering Methylene Aqueous solution 010405 organic chemistry Ligand 2500 General Materials Science 0104 chemical sciences Ruthenium General Energy chemistry Catalytic oxidation 2304 Environmental Chemistry |
| Zdroj: | ChemSusChem. 10:4517-4525 |
| ISSN: | 1864-5631 |
| DOI: | 10.1002/cssc.201701747 |
| Popis: | Ruthenium complexes containing the pentapyridyl ligand 6,6′′-(methoxy(pyridin-2-yl)methylene)di-2,2′-bipyridine (L-OMe) of general formula trans-[RuII(X)(L-OMe-κ-N5)]n+ (X=Cl, n=1, trans-1+; X=H2O, n=2, trans-22+) have been isolated and characterized in solution (by NMR and UV/Vis spectroscopy) and in the solid state by XRD. Both complexes undergo a series of substitution reactions at oxidation state RuII and RuIII when dissolved in aqueous triflic acid–trifluoroethanol solutions as monitored by UV/Vis spectroscopy, and the corresponding rate constants were determined. In particular, aqueous solutions of the RuIII-Cl complex trans-[RuIII(Cl)(L-OMe-κ-N5)]2+ (trans-12+) generates a family of Ru aquo complexes, namely trans-[RuIII(H2O)(L-OMe-κ-N5)]3+ (trans-23+), [RuIII(H2O)2(L-OMe-κ-N4)]3+ (trans-33+), and [RuIII(Cl)(H2O)(L-OMe-κ-N4)]2+ (trans-42+). Although complex trans-42+ is a powerful water oxidation catalyst, complex trans-23+ has only a moderate activity and trans-33+ shows no activity. A parallel study with related complexes containing the methyl-substituted ligand 6,6′′-(1-pyridin-2-yl)ethane-1,1-diyl)di-2,2′-bipyridine (L-Me) was carried out. The behavior of all of these catalysts has been rationalized based on substitution kinetics, oxygen evolution kinetics, electrochemical properties, and density functional theory calculations. The best catalyst, trans-42+, reaches turnover frequencies of 0.71 s−1 using CeIV as a sacrificial oxidant, with oxidative efficiencies above 95 %. |
| Databáze: | OpenAIRE |
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