Título:
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Ru water oxidation catalysts based on py5 ligands
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Autor/a:
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Gil-Sepulcre, Marcos; Schilling, Michael; Boehler, Mauro; Bozoglian, Fernando; Bachmann, Cyril; Scherrer, Dominik; Fox, Thomas; Spinlger, Bernhard; Gimbert-Suriñach, Carolina; Alberto, Roger; Bofill, Roger; Sala, Xavier; Luber, Sandra; Richmond, Craig; Llobet, Antoni
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Abstract:
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Ru 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-k-N5)]n+ (X = Cl, n = 1, trans-1+; X = H2O, n = 2, trans-22+) have been isolated and characterized in solution (NMR, UV-Vis) and in the solid state by XRD. Both complexes suffer a series of substitution reactions at oxidation state II and III, when dissolved in aqueous triflic acid-trifluroethanol solutions that have been monitored by UV-vis spectroscopy and their corresponding rate constants reported. In particular, aqueous solutions of the RuIII-Cl complex trans-[RuIII(Cl)(L-OMe-k-N5)]2+ (trans-12+) generates a family of Ru-aqua complexes namely trans-[RuIII(H2O)(L-OMe-k-N5)]3+ (trans-23+), [RuIII(H2O)2(L-OMe-k-N4)]3+ (trans-33+) and [RuIII(Cl)(H2O)(L-OMe-k-N4)]3+ (trans-42+). While complex trans-42+ is a powerful water oxidation catalyst, complex trans-23+ has only a moderate activity and trans-33+ is not a catalyst. Further, a parallel work has been carried out with related complexes but containing the methyl substituted ligand 6,6''-(1-pyridin-2-yl)ethane-1,1-diyl)di-2,2'-bipyridine (L-Me). The behavior of all these catalysts has been rationalized based on substitution kinetics, oxygen evolution kinetics, electrochemical properties and DFT calculations. The best catalysts, trans-42+, reach turnover frequencies of 0.71 s-1 using Ce(IV) as a sacrificial chemical oxidant with oxidative efficiencies above 95% |
Fecha de creación:
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2017 |
Materia(s):
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water oxidation catalysis, ruthenium complexes, substitution reactions, kinetics, pentapyridyl ligand |
Derechos:
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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
Tipo de documento:
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Artículo |
DOI:
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https://dx.doi.org/10.1002/cssc.201701747
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Editor:
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Wiley
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Publish at:
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ChemSusChem
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Compartir:
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