Electrocatalytic hydrogenation on poly[RhIII(L)2(Cl)2]+ (L=pyrrole-substituted 2,2′-bipyridine or 1,10-phenanthroline) films electrodes

Chardon‐Noblat, Sylvie; Oliveira, Ione Maria Ferreira de; Moutet, Jean‐Claude; Tingry, Sophie

doi:10.1016/1381-1169(95)00015-1

Cited by 26 publications

(6 citation statements)

References 9 publications

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“…Nevertheless, the electrochemical behavior of such Rh(III) hydrides species, and hence their reduction potential, has never been reported even in organic solvent, which is a more appropriate medium than water to obtain reliable electrochemical data. Our group has previously reported the elaboration of modified electrodes with polypyrrole films functionalized by such Rh(III) complexes for electrocatalytic hydrogen evolution and hydrogenation of organic compounds, but the corresponding hydrides were never electrochemically characterized. The determination of the redox properties of the hydride species should provide valuable information about the mechanism involved in the catalytic hydrogen evolution.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

et al. 2018

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We previously reported that the [Rh(dmbpy)Cl] (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) complex is an efficient H-evolving catalyst in water when used in a molecular homogeneous photocatalytic system for hydrogen production with [Ru(bpy)] (bpy = 2,2'-bipyridine) as photosensitizer and ascorbic acid as sacrificial electron donor. The catalysis is believed to proceed via a two-electron reduction of the Rh(III) catalyst into the square-planar [Rh(dmbpy)], which reacts with protons to form a Rh(III) hydride intermediate that can, in turn, release H following different pathways. To improve the current knowledge of these key intermediate species for H production, we performed herein a detailed electrochemical investigation of the [Rh(dmbpy)Cl] and [Rh(dtBubpy)Cl] (dtBubpy = 4,4'-di- tert-butyl-2,2'-bipyridine) complexes in CHCN, which is a more appropriate medium than water to obtain reliable electrochemical data. The low-valent [Rh(Rbpy)] and, more importantly, the hydride [Rh(Rbpy)(H)Cl] species (R = dm or dtBu) were successfully electrogenerated by bulk electrolysis and unambiguously spectroscopically characterized. The quantitative formation of the hydrides was achieved in the presence of weak proton sources (HCOOH or CFCOH), owing to the fast reaction of the electrogenerated [Rh(Rbpy)] species with protons. Interestingly, the hydrides are more difficult to reduce than the initial Rh(III) bis-chloro complexes by ∼310-340 mV. Besides, 0.5 equiv of H is generated through their electrochemical reduction, showing that Rh(III) hydrides are the initial catalytic molecular species for hydrogen evolution. Density functional theory calculations were also performed for the dmbpy derivative. The optimized structures and the theoretical absorption spectra were calculated for the initial bis-chloro complex and for the various rhodium intermediates involved in the H evolution process.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

et al. 2018

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“…Indeed, phosphonic acids are known to provide a more stable bonding to metal oxide than carboxylic acid, a key feature for this application as the system will be inevitably exposed to water and/or acidic conditions. In this study, we have tested several complexes as catalysts such as cobalt macrocyclic (cobaloxime and a cobalt-tetraaza derivative − ) and cobalt and rhodium polypyridyl derivatives − as these compounds are among the most active hydrogen-evolving catalysts reported so far (see Scheme ).…”

Section: Introductionmentioning

confidence: 99%

Visible Light-Driven Electron Transfer from a Dye-Sensitizedp-Type NiO Photocathode to a Molecular Catalyst in Solution: Toward NiO-Based Photoelectrochemical Devices for Solar Hydrogen Production

et al. 2015

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International audienceThe photoelectrochemical activity of a mesoporous NiO electrode sensitized by a ruthenium complex was investigated with several rhodium and cobalt H-2-evolving catalysts. Photocurrent as high as 80 mu A/cm(2) was produced by irradiation of such photocathode in the presence of the Rh(III) polypyridyl complexes, while cobalt complexes gave almost no photocurrent. Photolysis experiments led to the two-electron reduced form of the Rh(III) complexes into Rh(I) complexes and demonstrate the occurrence of an electron transfer chain from NiO to the catalyst. Mott-Schottky experiments evidenced the pH dependence of the NiO flat band potential, explaining the dramatic drop of the photocurrent in acidic conditions (cyanoanilinium). By contrast, in weaker acid conditions (formic acid) the photocurrent increases and the key Rh(III) hydride intermediate was efficiently generated. In acetonitrile solution, Rh(III)-H slowly reacts with HCOOH to generate H-2. However, this process was not catalytic, because the reduction potential of the Ru sensitizer is not sufficiently negative to reduce the Rh(III)-H into Rh(II)-H

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“…Bipyridine-pyrrole ligands L utilized for the electropolymerization of Rh complexes on carbon electrodes and proposed mechanism for the electroreduction of ketones catalyzed by polypyrrole-[Rh III (bpy) 2 (Cl) 2 )], X = ketone, XH 2 = alcohol [88][89][90] The complex [Ru(tpy)(bpy)(MeCN)] 2+ 38 is active in the electrohydrogenation of propan-2-ol with water as the proton source, though, with a rather low FE of only 28% and a TON of 1.8, as H 2 is the dominant product (FE for H 2 65%). 91 Ru complex 38 is reduced reversibly at -1.01 V and -1.31 V vs. NHE in MeCN.…”

Section: Scheme 19mentioning

confidence: 99%

“…88b The stability of the systems depends on the linker between the pyrrole and the pyridine in the bpy ligand. 88,89 An alkyl chain proved to be rather stable, whereas the catalytic activity drops quickly if an ester linkage is utilized, most likely due to hydrolysis of the ester and complex leaching. Enantioselective hydrogenations of ketones using homogeneous or electropolymerized Rh complexes with chiral bpy derivatives were rather unsuccessful (Scheme 19); the ee of the products were all very low (5-15% ee).…”

Section: Electrochemical Protocolsmentioning

confidence: 99%

Transition Metal Complex Catalyzed Photo- and Electrochemical (De)hydrogenations Involving C=O and C=N Bonds

2021

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Herein, we summarize the photo- and electrochemical protocols for dehydrogenation and hydrogenations involving carbonyl and imine functions. The three basic principles that have been explored to interconvert such moieties with transition metal complexes are discussed in detail and the substrate scope is evaluated. Furthermore, we describe some general thermodynamic and kinetic aspects of such electro- and photochemically driven reactions.

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Electrocatalytic hydrogenation on poly[RhIII(L)2(Cl)2]+ (L=pyrrole-substituted 2,2′-bipyridine or 1,10-phenanthroline) films electrodes

Cited by 26 publications

References 9 publications

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

Visible Light-Driven Electron Transfer from a Dye-Sensitizedp-Type NiO Photocathode to a Molecular Catalyst in Solution: Toward NiO-Based Photoelectrochemical Devices for Solar Hydrogen Production

Transition Metal Complex Catalyzed Photo- and Electrochemical (De)hydrogenations Involving C=O and C=N Bonds

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Electrocatalytic hydrogenation on poly[RhIII(L)2(Cl)2]+ (L=pyrrole-substituted 2,2′-bipyridine or 1,10-phenanthroline) films electrodes

Cited by 26 publications

References 9 publications

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H2-Evolving Catalysts

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H2-Evolving Catalysts

Visible Light-Driven Electron Transfer from a Dye-Sensitizedp-Type NiO Photocathode to a Molecular Catalyst in Solution: Toward NiO-Based Photoelectrochemical Devices for Solar Hydrogen Production

Transition Metal Complex Catalyzed Photo- and Electrochemical (De)hydrogenations Involving C=O and C=N Bonds

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Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts