dc.contributor.author
Boniolo, Manuel
dc.contributor.author
Hossain, Md Kamal
dc.contributor.author
Chernev, Petko
dc.contributor.author
Suremann, Nina F.
dc.contributor.author
Heizmann, Philipp A.
dc.contributor.author
Lyvik, Amanda S. L.
dc.contributor.author
Beyer, Paul
dc.contributor.author
Haumann, Michael
dc.contributor.author
Huang, Ping
dc.contributor.author
Salhi, Nessima
dc.date.accessioned
2022-08-08T06:45:14Z
dc.date.available
2022-08-08T06:45:14Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/35785
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-35500
dc.description.abstract
The design of molecular water oxidation catalysts (WOCs) requires a rational approach that considers the intermediate steps of the catalytic cycle, including water binding, deprotonation, storage of oxidizing equivalents, O–O bond formation, and O2 release. We investigated several of these properties for a series of base metal complexes (M = Mn, Fe, Co, Ni) bearing two variants of a pentapyridyl ligand framework, of which some were reported previously to be active WOCs. We found that only [Fe(Py5OMe)Cl]+ (Py5OMe = pyridine-2,6-diylbis[di-(pyridin-2-yl)methoxymethane]) showed an appreciable catalytic activity with a turnover number (TON) = 130 in light-driven experiments using the [Ru(bpy)3]2+/S2O82– system at pH 8.0, but that activity is demonstrated to arise from the rapid degradation in the buffered solution leading to the formation of catalytically active amorphous iron oxide/hydroxide (FeOOH), which subsequently lost the catalytic activity by forming more extensive and structured FeOOH species. The detailed analysis of the redox and water-binding properties employing electrochemistry, X-ray absorption spectroscopy (XAS), UV–vis spectroscopy, and density-functional theory (DFT) showed that all complexes were able to undergo the MIII/MII oxidation, but none was able to yield a detectable amount of a MIV state in our potential window (up to +2 V vs SHE). This inability was traced to (i) the preference for binding Cl– or acetonitrile instead of water-derived species in the apical position, which excludes redox leveling via proton coupled electron transfer, and (ii) the lack of sigma donor ligands that would stabilize oxidation states beyond MIII. On that basis, design features for next-generation molecular WOCs are suggested.
en
dc.format.extent
15 Seiten
dc.rights.uri
https://creativecommons.org/licenses/by/4.0/
dc.subject
Redox reactions
en
dc.subject.ddc
500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften
dc.title
Water Oxidation by Pentapyridyl Base Metal Complexes? A Case Study
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.doi
10.1021/acs.inorgchem.2c00631
dcterms.bibliographicCitation.journaltitle
Inorganic Chemistry
dcterms.bibliographicCitation.number
24
dcterms.bibliographicCitation.pagestart
9104
dcterms.bibliographicCitation.pageend
9118
dcterms.bibliographicCitation.volume
61
dcterms.bibliographicCitation.url
https://doi.org/10.1021/acs.inorgchem.2c00631
refubium.affiliation
Physik
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access
dcterms.isPartOf.eissn
1520-510X
refubium.resourceType.provider
WoS-Alert