Tricopper-polyoxometalate catalysts for water oxidation: Redox-inertness of copper center

Su, Xiaofang; Guan, Wei; Yan, Likai; Su, Zhong‐Min

doi:10.1016/j.jcat.2019.11.025

Cited by 14 publications

(13 citation statements)

References 61 publications

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“…12 ), suggesting that any H 2 O 2 eventually formed in solution as a consequence of oxygen reduction, was not responsible for the observed cleavage. This is in contrast with previous mechanistic proposals which suggested H 2 O 2 as an intermediate in similar reactions 68 , and implies that a mild oxidant species formed through the reaction of Cu I WD and O 2 might be enabling HEWL oxidative cleavage 73 , 74 .…”

Section: Resultscontrasting

confidence: 79%

Regioselective protein oxidative cleavage enabled by enzyme-like recognition of an inorganic metal oxo cluster ligand

et al. 2023

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Oxidative modifications of proteins are key to many applications in biotechnology. Metal-catalyzed oxidation reactions efficiently oxidize proteins but with low selectivity, and are highly dependent on the protein surface residues to direct the reaction. Herein, we demonstrate that discrete inorganic ligands such as polyoxometalates enable an efficient and selective protein oxidative cleavage. In the presence of ascorbate (1 mM), the Cu-substituted polyoxometalate K8[Cu2+(H2O)(α2-P2W17O61)], (CuIIWD, 0.05 mM) selectively cleave hen egg white lysozyme under physiological conditions (pH =7.5, 37 °C) producing only four bands in the gel electropherogram (12.7, 11, 10, and 5 kDa). Liquid chromatography/mass spectrometry analysis reveals a regioselective cleavage in the vicinity of crystallographic CuIIWD/lysozyme interaction sites. Mechanistically, polyoxometalate is critical to position the Cu at the protein surface and limit the generation of oxidative species to the proximity of binding sites. Ultimately, this study outlines the potential of discrete, designable metal oxo clusters as catalysts for the selective modification of proteins through radical mechanisms under non-denaturing conditions.

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Section: Resultscontrasting

confidence: 79%

Regioselective protein oxidative cleavage enabled by enzyme-like recognition of an inorganic metal oxo cluster ligand

et al. 2023

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“…POMs as structurally rigid and stable molecular metal oxo clusters have been well recognized as efficient WOCs owing to their capability to drive fast and reversible multi-electron transfer transformations, while preserving their structural motifs. [138][139][140] 141 For a more detailed discussion of POM-based water splitting catalysts, we would like to recommend recent representative reviews. 142,143 As evident from the above discussion, molecular compounds offer a wide variety of options in the strategic design of efficient WOCs.…”

Section: Chem Soc Rev Review Articlementioning

confidence: 99%

Molecular and heterogeneous water oxidation catalysts: recent progress and joint perspectives

et al. 2021

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“…Polyoxometalates (POMs), a diverse family of anionic metal-oxygen species, are recognized as one of the promising catalysts for oxidation reactions. − In addition, the exposed oxygen ligands on the surface of POM are remarkably basic and thus can accept protons derived from the substrate, which significantly promotes catalytic reactions. − In recent years, the catalytic activity of POM derivatives in various organic oxidation reactions including oxidation of alkane, alcohol, benzene, aldehyde, and amine has been demonstrated by Wei and co-workers, − Neumann and co-workers, − Kholdeeva and co-workers, − Weinstock and co-workers, − and Proust et al Most notably, the organic oxidation reaction catalyzed by POM derivatives operates with oxygen (O 2 ) or hydrogen peroxide (H 2 O 2 ) as a moderate and environmentally benign oxidant.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Insight into Oxidation of Anilines to Azobenzenes Catalyzed by Hexamolybdate: Outer-Sphere Electron and Proton Transfer

Wei

et al. 2023

J. Phys. Chem. C

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Recently, the catalytic activity of Lindqvist-type hexamolybdate [Mo6O19]2– in the oxidation of an aniline derivative (LPhNH2, L = substituent) was demonstrated by Wei and co-workers (Angew. Chem. Int. Ed. 2021, 60, 6382–6385). Herein, taking phenylamine (PhNH2) oxidation to azobenzene (PhNNPh) as a model reaction, we report the density functional theory investigation of the catalytic mechanism of [Mo6O19]2– and illustrate the critical experimental phenomena. During the catalytic reaction, once the preassociation of [Mo6O19]2– and PhNH2 takes place, electron transfer and proton transfer immediately proceed to form an N radical intermediate. The higher the highest occupied molecular orbital energy of the substrate, the easier the formation of the N radical intermediate. The N–N bond formation proceeds via the second PhNH2 nucleophilic attack on the N radical intermediate. The substituent position and the N reaction site of the substrate have a significant effect on the second PhNH2 nucleophilic attack process. In the reaction process, the six MoVI of [Mo6O19]2– are still hexacoordinated, which is defined as the outer-sphere pathway. One of the factors determining the product selectivity is the electrostatic repulsion between LPhNH2 and the N radical intermediate. The experiment reveals that the product yield is increased by the addition of Na2S2O3, while the catalytic reaction is completely deactivated with Na2CO3 or K3PO4. Based on the proposed mechanism, the experimental observation was rationalized. The S2O3 2– part of Na2S2O3 has a similar function as the electron-withdrawing substituent due to its low lowest unoccupied molecular orbital (LUMO) energy, which reduces the LUMO energy of the N radical intermediate and thus facilitates PhNH2 nucleophilic attack, while the CO3 2– part of Na2CO3 or PO4 3– part of K3PO4 has an undesirable effect on the electrophilicity of the N radical intermediate, resulting in the interruption of the catalytic reaction. This work would provide a detailed understanding of the catalytic reaction.

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Tricopper-polyoxometalate catalysts for water oxidation: Redox-inertness of copper center

Cited by 14 publications

References 61 publications

Regioselective protein oxidative cleavage enabled by enzyme-like recognition of an inorganic metal oxo cluster ligand

Regioselective protein oxidative cleavage enabled by enzyme-like recognition of an inorganic metal oxo cluster ligand

Molecular and heterogeneous water oxidation catalysts: recent progress and joint perspectives

Theoretical Insight into Oxidation of Anilines to Azobenzenes Catalyzed by Hexamolybdate: Outer-Sphere Electron and Proton Transfer

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