Iron Pentapyridyl Complexes as Molecular WaterOxidation Catalysts: Strong Influence of a Chloride Ligandand pH in Altering the Mechanism
2016 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 10, 1178-1186 p.Article in journal (Refereed) Published
The development of molecular water oxidation catalysts basedon earth-abundant, non-noble metals is essential for artificial photosynthesis research. Iron, which is the most abundant transition metal in the earth's crust, is a prospective candidate for this purpose. Herein, we report two iron complexes based on the polypyridyl ligand Py5OH (Py5OH=pyridine-2,6-diylbis[di(pyridin-2-yl)methanol]) that can catalyse water oxidation to produce O2 in RuIII-induced (at pH 8, highest turnover number (TON)=26.5; turnover frequency (TOF)=2.2 s-1), CeIV-induced(at pH 1.5 highest TON=16; TOF=0.75 s-1) and photo-induced(at pH 8, highest TON=43.5; TOF=0.6 s-1) reactions. A chloride ligand in one of the iron complexes is shown to affect the activity strongly, improve stability and, thereby, the performance at pH 8 but it inhibits oxygen evolution at pH 1.5. The observations are consistent with a change in mechanism for catalytic water oxidation with the Fe(Py5OH) complexes between acidic (CeIV) and near-neutral pH (RuIII).
Place, publisher, year, edition, pages
2016. Vol. 9, no 10, 1178-1186 p.
homogeneous catalysis, iron, oxidation, reaction mechanisms, water splitting
Research subject Chemistry with specialization in Molecular Biomimetics
IdentifiersURN: urn:nbn:se:uu:diva-292976DOI: 10.1002/cssc.201600052ISI: 000378635500016PubMedID: 27114078OAI: oai:DiVA.org:uu-292976DiVA: diva2:927181
FunderKnut and Alice Wallenberg Foundation, 2011.0067Swedish Energy Agency, 11674-5Swedish Research Council