Ligand Geometry Directs OO Bond‐Formation Pathway in Ruthenium‐Based Water Oxidation Catalyst

Maji, Somnath; Vigara, Laura; Cottone, Francesca; Bozoglián, Fernando; Benet‐Buchholz, Jordi; Llobet, Antoni

doi:10.1002/anie.201201356

Cited by 63 publications

(41 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The cis complex did not form due to steric constraints. Complex 20 was found to be active in catalyzing H 2 O oxidation, when using Ce IV 169 Later, Thummel and co-workers synthesized a series of dinuclear complexes (22−34) that also contained rigid polypyridyl-based ligands as the bridge between the two ruthenium centers ( Figure 11). The authors were interested in evaluating the effect that the axial ligands exerted on the properties and catalytic activity of the corresponding dinuclear ruthenium complexes.…”

Section: Scheme 4 Comparison Of (A) Direct Reoxidation By Molecular mentioning

confidence: 98%

Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation

et al. 2014

View full text Add to dashboard Cite

Section: Scheme 4 Comparison Of (A) Direct Reoxidation By Molecular mentioning

confidence: 98%

Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation

et al. 2014

View full text Add to dashboard Cite

“…Recent reports on a series of Ru-WOCs demonstrate strongly accelerated catalysis through ligand-enhanced oxo-coupling. 29–31 …”

Section: Introductionmentioning

confidence: 99%

“…Since facile S–T interconversion was found for the formal (V) oxidation state (<5 kcal/mol), both pathways might be accessible through ligand control as in the related ruthenium chemistry. 29 In Figure 1 only coupling pathways from the formal (V) oxidation state are shown for the sake of simplicity, but other, potentially lower-energy, ROC pathways might be accessible from lower formal oxidation states (i.e., the doublet Ir(IV)). 42 In order to experimentally probe the viability of ROC mechanisms in Ir-catalyzed WO, we prepared some dimeric Cp*Ir III precursors and investigated their oxidative stabilities, kinetics in WO catalysis, and electrochemical behaviors, all compared to their respective monomers.…”

Section: Introductionmentioning

confidence: 99%

Probing the Viability of Oxo-Coupling Pathways in Iridium-Catalyzed Oxygen Evolution

et al. 2013

View full text Add to dashboard Cite

A series of Cp*IrIII dimers have been synthesized to elucidate the mechanistic viability of radical oxo-coupling pathways in iridium-catalyzed O2 evolution. The oxidative stability of the precursors toward nanoparticle formation and their oxygen evolution activity have been investigated and compared to suitable monomeric analogues. We found that precursors bearing monodentate NHC ligands degraded to form nanoparticles (NPs), and accordingly their O2 evolution rates were not significantly influenced by their nuclearity or distance between the two metals in the dimeric precursors. A doubly chelating bis-pyridine–pyrazolide ligand provided an oxidation-resistant ligand framework that allowed a more meaningful comparison of catalytic performance of dimers with their corresponding monomers. With sodium periodate (NaIO4) as the oxidant, the dimers provided significantly lower O2 evolution rates per [Ir] than the monomer, suggesting a negative interaction instead of cooperativity in the catalytic cycle. Electrochemical analysis of the dimers further substantiates the notion that no radical oxyl-coupling pathways are accessible. We thus conclude that the alternative path, nucleophilic attack of water on high-valent Ir-oxo species, may be the preferred mechanistic pathway of water oxidation with these catalysts, and bimolecular oxo-coupling is not a valid mechanistic alternative as in the related ruthenium chemistry, at least in the present system.

show abstract

“…[6,16] Furthermore,almost all the reported catalysts function in the presence of organic solvent, which might lead to undesired deactivation pathways and increase the complexity of an already very complex reaction since the high thermodynamic redox potential needed for water oxidation permits the catalyst to oxidize abroad range of organic and inorganic substrates.…”

Section: Tomeetthesustainableproductionofcleanenergydemandsmentioning

confidence: 99%

Self‐Assembled Amphiphilic Water Oxidation Catalysts: Control of O−O Bond Formation Pathways by Different Aggregation Patterns

et al. 2016

View full text Add to dashboard Cite

The oxidation of water to molecular oxygen is the key step to realize water splitting from both biological and chemical perspective. In an effort to understand how water oxidation occurs on a molecular level, a large number of molecular catalysts have been synthesized to find an easy access to higher oxidation states as well as their capacity to make O-O bond. However, most of them function in a mixture of organic solvent and water and the O-O bond formation pathway is still a subject of intense debate. Herein, we design the first amphiphilic Ru-bda (H2 bda=2,2'-bipyridine-6,6'-dicarboxylic acid) water oxidation catalysts (WOCs) of formula [Ru(II) (bda)(4-OTEG-pyridine)2 ] (1, OTEG=OCH2 CH2 OCH2 CH2 OCH3 ) and [Ru(II) (bda)(PySO3 Na)2 ] (2, PySO3 (-) =pyridine-3-sulfonate), which possess good solubility in water. Dynamic light scattering (DLS), scanning electron microscope (SEM), critical aggregation concentration (CAC) experiments and product analysis demonstrate that they enable to self-assemble in water and form the O-O bond through different routes even though they have the same bda(2-) backbone. This work illustrates for the first time that the O-O bond formation pathway can be regulated by the interaction of ancillary ligands at supramolecular level.

show abstract

Ligand Geometry Directs OO Bond‐Formation Pathway in Ruthenium‐Based Water Oxidation Catalyst

Cited by 63 publications

References 32 publications

Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation

Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation

Probing the Viability of Oxo-Coupling Pathways in Iridium-Catalyzed Oxygen Evolution

Self‐Assembled Amphiphilic Water Oxidation Catalysts: Control of O−O Bond Formation Pathways by Different Aggregation Patterns

Contact Info

Product

Resources

About