A Calix[4]arene‐Based Cyclic Dinuclear Ruthenium Complex for Light‐Driven Catalytic Water Oxidation

Noll, Niklas; Würthner, Frank

doi:10.1002/chem.202004486

Cited by 21 publications

(25 citation statements)

References 82 publications

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“…In many cases it is not clear whether e.g., the sum of various visible light-driven electron transfer processes to activate the catalyst or turnover at the photochemically activated catalyst represented the bottleneck. Some insights are only available for intermolecular light-driven water oxidations 12 , 13 .…”

Section: Introductionmentioning

confidence: 99%

Outpacing conventional nicotinamide hydrogenation catalysis by a strongly communicating heterodinuclear photocatalyst

et al. 2022

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Unequivocal assignment of rate-limiting steps in supramolecular photocatalysts is of utmost importance to rationally optimize photocatalytic activity. By spectroscopic and catalytic analysis of a series of three structurally similar [(tbbpy)2Ru-BL-Rh(Cp*)Cl]3+ photocatalysts just differing in the central part (alkynyl, triazole or phenazine) of the bridging ligand (BL) we are able to derive design strategies for improved photocatalytic activity of this class of compounds (tbbpy = 4,4´-tert-butyl-2,2´-bipyridine, Cp* = pentamethylcyclopentadienyl). Most importantly, not the rate of the transfer of the first electron towards the RhIII center but rather the rate at which a two-fold reduced RhI species is generated can directly be correlated with the observed photocatalytic formation of NADH from NAD+. Interestingly, the complex which exhibits the fastest intramolecular electron transfer kinetics for the first electron is not the one that allows the fastest photocatalysis. With the photocatalytically most efficient alkynyl linked system, it is even possible to overcome the rate of thermal NADH formation by avoiding the rate-determining β-hydride elimination step. Moreover, for this photocatalyst loss of the alkynyl functionality under photocatalytic conditions is identified as an important deactivation pathway.

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Section: Introductionmentioning

confidence: 99%

Outpacing conventional nicotinamide hydrogenation catalysis by a strongly communicating heterodinuclear photocatalyst

et al. 2022

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“…Although trinuclear macrocyclic Ru complexes have been reported for the first time in 2016, [11a] and several noncyclic di‐ and trinuclear Ru WOCs have been developed in the past decade, [8,9] reports on such cyclic Ru complexes are still scarce. Most recently, our group has reported a dinuclear macrocyclic Ru complex containing calix[4]arene‐based axial ligands that exhibits unexpectedly high catalytic performance in chemically‐driven and photocatalytic water oxidation [14] . In the present study, hitherto unknown di‐ and tetranuclear Ru(bda) macrocycles bearing 1,3‐ and 1,4‐bipyridyl benzene axial ligands have been constructed by using non‐linear derivatives of the bridging ligands of MC3 and the catalytic activities of the homologous series of di‐, tri‐, and tetranuclear macrocyclic complexes OEG‐MC2 , OEG‐MC3 and OEG‐MC4 studied in a comparative manner.…”

Section: Introductionmentioning

confidence: 99%

Structure‐Activity Relationship for Di‐ up to Tetranuclear Macrocyclic Ruthenium Catalysts in Homogeneous Water Oxidation

Schindler

Meza-Chincha

Roth

et al. 2021

Chemistry A European J

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Two di-and tetranuclear Ru(bda) (bda: 2,2'-bipyridine-6,6'-dicarboxylate) macrocyclic complexes were synthesized and their catalytic activities in chemical and photochemical water oxidation investigated in a comparative manner to our previously reported trinuclear congener. Our studies have shown that the catalytic activities of this homologous series of multinuclear Ru(bda) macrocycles in homogeneous water oxidation are dependent on their size, exhibiting highest efficiencies for the largest tetranuclear catalyst. The turnover frequencies (TOFs) have increased from di-to tetranuclear macrocycles not only per catalyst molecule but more importantly also per Ru unit with TOF of 6 s À 1 to 8.7 s À 1 and 10.5 s À 1 in chemical and 0.6 s À 1 to 3.3 s À 1 and 5.8 s À 1 in photochemical water oxidation per Ru unit, respectively. Thus, for the first time, a clear structure-activity relationship could be established for this novel class of macrocyclic water oxidation catalysts.

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“…Supramolecular strategies could alleviate this paradox in two ways: covalent linking monomeric catalyst or pre-organizing two monomeric units non-covalently at an appropriate distance. , Di-, , tri-, − and tetra-nuclear Ru-bda-based water oxidation catalysts have been synthesized and showed increased activities, indicating the reliability of the strategy. However, considering the complexity of the synthesis of multinuclear structures, non-covalent assembly strategies seem more attractive.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Interactions of Ru-bda-Type Catalysts for Promoting Water Oxidation Activity

Liu

Shen

et al. 2021

Energy Fuels

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The catalytic activity of the bimolecular reaction was affected by many parameters. Although many efforts have been dedicated to investigate the influence of secondary interactions in pre-organizing catalysts, the hydrophobic effect on Ru-bda-type water oxidation catalysts remains unclear as a result of the lack of an ideal catalytic model. In this work, four catalysts 1–4 with variable hydrophobicity have been synthesized, and cerium(IV)-driven water oxidation results showed that the hydrophobic complexes 3 and 4 outperformed the hydrophilic complex 2. Steric mapping, nuclear magnetic resonance, and differential pulse voltammogram studies indicated that the increase in activity has no correlation with electronic and steric effects but has correlation with hydrophobicity. Molecular dynamics have shown that the modifications of the hydrophobicity on the axial pyridine ligands of the Ru-bda type of catalysts can improve the water oxidation catalytic activity by stabilizing the pre-reactive catalyst dimer.

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A Calix[4]arene‐Based Cyclic Dinuclear Ruthenium Complex for Light‐Driven Catalytic Water Oxidation

Cited by 21 publications

References 82 publications

Outpacing conventional nicotinamide hydrogenation catalysis by a strongly communicating heterodinuclear photocatalyst

Outpacing conventional nicotinamide hydrogenation catalysis by a strongly communicating heterodinuclear photocatalyst

Structure‐Activity Relationship for Di‐ up to Tetranuclear Macrocyclic Ruthenium Catalysts in Homogeneous Water Oxidation

Hydrophobic Interactions of Ru-bda-Type Catalysts for Promoting Water Oxidation Activity

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