Room-Temperature Characterization of a Mixed-Valent μ-Hydroxodicopper(II,III) Complex

Isaac, James A.; Gennarini, Federica; López, Isidoro; Thibon-Pourret, Aurore; David, Rolf; Gellon, Gisèle; Génnaro, Béatrice; Philouze, Christian; Meyer, Franc; Demeshko, Serhiy; Mest, Yves Le; Réglier, Marius; Jamet, Hélène; Poul, Nicolas Le; Belle, Catherine

doi:10.1021/acs.inorgchem.6b01504

Cited by 26 publications

(70 citation statements)

References 31 publications

(42 reference statements)

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“…Consequently,i mproving the hydroxylationy ield requireds uccessive pH adjustments during bulk electrolysis. [61][62][63][64][65] Interestingly, no deprotonation of the hydroxo bridges has been evidencedu pon monoelectronic oxidation of hydroxo-bridged dinuclearC u II complexes in organic solvents. At this point, the nature of the oxidizing speciesr esponsible for the oxygen atom transfer reaction remains difficult to ascertain.…”

Section: Discussionmentioning

confidence: 99%

“…Our best hydroxylation yield is 33 %; taking into account the speciation diagram,w hich indicates that 3 is formed with am aximum of 50 %o ft he Cu concentration, it is possible to estimate that 66 %o ft he initial precursor undergoes ah ydroxylation reaction. [61,62] Upon monoelectronic oxidation of complex 3,i ti st herefore possible that no deprotonation of the hydroxo bridges occurs, leading to the dinuclear [(IndPY2) 2 Cu II Cu III (m-OH) 2 ] 3 + species( 4)t hat could be responsible for oxidative reactivity ( Figure 6). Oxidation of dinuclear precursor 3 occurs at 1.30 V versus NHE.…”

Section: Discussionmentioning

confidence: 99%

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Electrochemical Water Oxidation and Stereoselective Oxygen Atom Transfer Mediated by a Copper Complex

Kafentzi

Papadakis

Gennarini

et al. 2018

Chemistry A European J

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Water oxidation by copper-based complexes to form dioxygen has attracted attention in recent years, with the aim of developing efficient and cheap catalysts for chemical energy storage. In addition, high-valent metal-oxo species produced by the oxidation of metal complexes in the presence of water can be used to achieve substrate oxygenation with the use of H O as an oxygen source. To date, this strategy has not been reported for copper complexes. Herein, a copper(II) complex, [(RPY2)Cu(OTf) ] (RPY2=N-substituted bis[2-pyridyl(ethylamine)] ligands; R=indane; OTf=triflate), is used. This complex, which contains an oxidizable substrate moiety (indane), is used as a tool to monitor an intramolecular oxygen atom transfer reaction. Electrochemical properties were investigated and, upon electrolysis at 1.30 V versus a normal hydrogen electrode (NHE), both dioxygen production and oxygenation of the indane moiety were observed. The ligand was oxidized in a highly diastereoselective manner, which indicated that the observed reactivity was mediated by metal-centered reactive species. The pH dependence of the reactivity was monitored and correlated with speciation deduced from different techniques, ranging from potentiometric titrations to spectroscopic studies and DFT calculations. Water oxidation for dioxygen production occurs at neutral pH and is probably mediated by the oxidation of a mononuclear copper(II) precursor. It is achieved with a rather low overpotential (280 mV at pH 7), although with limited efficiency. On the other hand, oxygenation is maximum at pH 8-8.5 and is probably mediated by the electrochemical oxidation of an antiferromagnetically coupled dinuclear bis(μ-hydroxo) copper(II) precursor. This constitutes the first example of copper-centered oxidative water activation for a selective oxygenation reaction.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Electrochemical Water Oxidation and Stereoselective Oxygen Atom Transfer Mediated by a Copper Complex

Kafentzi

Papadakis

Gennarini

et al. 2018

Chemistry A European J

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“…378,379 The structurally defined dicopper(II) complexes 92 and 93 (Figure 66) were oxidized by 1-electron to yield species formulated as Cu(II)Cu(III) complexes on the basis of spectroscopic data. Both complexes exhibited axial EPR spectra consistent with a localized mixed-valent ground state, with additional support provided by DFT calculations.…”

Section: Dicopper Compoundsmentioning

confidence: 99%

“…Subtle differences in the UV – vis data were interpreted to indicate Robin-Day 380 class II behavior for 93 . 379 For the complex derived from 92 , an additional 1-electron oxidation was proposed to yield a dicopper(III) species on the basis of Cu K-edge XAS and UV – vis redox titration results. 378 DFT calculations supported retention of the hydroxo bridges in the oxidized complexes.…”

Section: Dicopper Compoundsmentioning

confidence: 99%

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Copper–Oxygen Complexes Revisited: Structures, Spectroscopy, and Reactivity

et al. 2017

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A longstanding research goal has been to understand the nature and role of copper–oxygen intermediates within copper-containing enzymes and abiological catalysts. Synthetic chemistry has played a pivotal role in highlighting the viability of proposed intermediates and expanding the library of known copper–oxygen cores. In addition to the number of new complexes that have been synthesized since the previous reviews on this topic in this journal (Mirica, L. M.; Ottenwaelder, X.; Stack, T. D. P. Chem. Rev. 2004, 104, 1013–1046 and Lewis, E. A.; Tolman, W. B. Chem. Rev. 2004, 104, 1047–1076), the field has seen significant expansion in the (1) range of cores synthesized and characterized, (2) amount of mechanistic work performed, particularly in the area of organic substrate oxidation, and (3) use of computational methods for both the corroboration and prediction of proposed intermediates. The scope of this review has been limited to well-characterized examples of copper–oxygen species but seeks to provide a thorough picture of the spectroscopic characteristics and reactivity trends of the copper–oxygen cores discussed.

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A Dicopper Platform that Stabilizes the Formation of Pentanuclear Coinage Metal Hydride Complexes

et al. 2020

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Reduction of a dicopper(II) bis(hydroxide) complex with silanes in the presence of external copper or silver cations results in the formation of multinuclear hydride clusters, which were characterized by a variety of NMR spectroscopic experiments and X‐ray crystallography. In particular, the pentanuclear complexes adopt an unusual planar “bow tie” configuration. The copper hydride complexes are efficient catalysts for the dehydrogenation of formic acid to H2 and CO2.

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Room-Temperature Characterization of a Mixed-Valent μ-Hydroxodicopper(II,III) Complex

Cited by 26 publications

References 31 publications

Electrochemical Water Oxidation and Stereoselective Oxygen Atom Transfer Mediated by a Copper Complex

Electrochemical Water Oxidation and Stereoselective Oxygen Atom Transfer Mediated by a Copper Complex

Copper–Oxygen Complexes Revisited: Structures, Spectroscopy, and Reactivity

A Dicopper Platform that Stabilizes the Formation of Pentanuclear Coinage Metal Hydride Complexes

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