Photochemical hydrogen production catalyzed by polypyridyl ruthenium–cobaloxime heterobinuclear complexes with different bridges

Li, Cheng; Wang, Mei; Pan, Jingxi; Zhang, Pan; Zhang, Rong; Sun, Licheng

doi:10.1016/j.jorganchem.2009.04.041

Cited by 113 publications

(81 citation statements)

References 38 publications

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“…catalytic efficiency can be tuned. [20][21][22][23][24][25] The intensively studied intramolecular photocatalyst [(tbbpy) 2 Ru(tpphz)PdCl 2 ](PF 6 ) 2 (Fig. 1, Ru(tpphz)PdCl 2 ; tbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine, tpphz = tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2′′′,3′′′-j]phenazine) is an active hydrogen evolving PDM generating H 2 with a maximum turnover number (TON) of 238.…”

Section: Introductionmentioning

confidence: 99%

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

et al. 2014

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Section: Introductionmentioning

confidence: 99%

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

et al. 2014

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“…Recent examples of intramolecular photocatalysts include water oxidation catalysts, water reduction catalysts and carbon dioxide reducing catalysts. [2][3][4][5][6][7][8][9][10][11] In direct comparison with intermolecular [12][13][14][15][16] and heterogeneous photocatalysts, [17][18][19][20] intramolecular photocatalysis, however, often suffer from lower catalytic activity. It is therefore of paramount importance to learn more about the factors determining the catalytic activity of intramolecular photocatalysts.…”

Section: Introductionmentioning

confidence: 99%

“…Route (ii) can be taken by screening properties of the catalytic system like solvent composition, pH value and ionic additives. 5,7,[23][24][25][26][27] Within this research, it has, for instance, been shown that the addition of N(C 4 H 9 ) 4 Cl to the photocatalytic system for the light induced formation of hydrogen from water based on [Ru(tbbpy) 2 (tpphz)-PdCl 2 ](PF 6 ) 2 (RutpphzPd) (ruthenium(II)-bis(4,4′-di-tert-butyl-2,2′-bipyridyl)-(μ-tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2′″,3′″-j]phenazine)-(dichloropalladium)-dihexafluorophosphate) ( Fig. 1) leads to a significant drop in catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular activation of a molecular photocatalyst

et al. 2014

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“…In the past four years, we and others reported on cobaloximes-cobalt complexes containing bridged bidentate oximato ligands (see Scheme 1)-(4-7) as a new class of such catalysts with good catalytic stability and Ϸ250-300 mV overvoltage-the difference between the observed catalytic potential and the thermodynamic H 2 /2H ϩ ϩ 2 e Ϫ equilibrium. To date, these catalysts are among the most efficient ones and, thus, are currently exploited for the construction of H 2 -evolving photocatalytic devices that actually rival previously reported systems using Pt nanoparticles as catalysts (8)(9)(10)(11)(12). However, despite the pseudomacrocyclic nature of their equatorial ligand, cobaloximes are prone to hydrolysis under acidic conditions: protonation at two oximato functions in the equatorial plane indeed results in the decomposition of the complex through the cleavage of the tetradentate macrocyclic ligand into two dioxime ligands and suppression of the chelate effect.…”

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confidence: 99%

Cobalt and nickel diimine-dioxime complexes as molecular electrocatalysts for hydrogen evolution with low overvoltages

Jacques

Artero

Pécaut

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

399

424

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Hydrogen production through the reduction of water appears to be a convenient solution for the long-run storage of renewable energies. However, economically viable hydrogen production requests platinum-free catalysts, because this expensive and scarce (only 37 ppb in the Earth's crust) metal is not a sustainable resource [Gordon RB, Bertram M, Graedel TE (2006) Proc Natl Acad Sci USA 103:1209 -1214]. Here, we report on a new family of cobalt and nickel diimine-dioxime complexes as efficient and stable electrocatalysts for hydrogen evolution from acidic nonaqueous solutions with slightly lower overvoltages and much larger stabilities towards hydrolysis as compared to previously reported cobaloxime catalysts. A mechanistic study allowed us to determine that hydrogen evolution likely proceeds through a bimetallic homolytic pathway. The presence of a proton-exchanging site in the ligand, furthermore, provides an exquisite mechanism for tuning the electrocatalytic potential for hydrogen evolution of these compounds in response to variations of the acidity of the solution, a feature only reported for native hydrogenase enzymes so far.bio-inspired chemistry ͉ cobaloxime ͉ electrocatalysis ͉ hydrogen evolution reaction ͉ hydrogenase H ydrogen production, through the reduction of water, appears to be a solution to consider for the long-run storage of renewable energetic resources (1). The hydrogen evolution reaction (her) is apparently a very simple reaction but, as with most multielectronic processes, it is a slow process that should be catalyzed. Nickel-based electrodes can be used for that aim in strongly alkaline media, but this technology results in average energetic yields (Ϸ50-70%), suffers from corrosion issues, and can hardly be miniaturized due to the lack of polymer exchange membrane (PEM) material that is stable under these conditions. Actually, technological research now focuses on PEM electrolytic cells for which carbon-supported platinum nanoparticles are generally used as catalysts. This scarce and expensive noble metal is, however, not a renewable resource. Thus, progress to a mature hydrogen economy depends on breakthroughs in finding new catalytic materials based on earth-abundant elements (2). To that aim, the combination of a common electrode material with a coordination complex of a first-row transition metal, able to catalyze the reaction at a potential close to the standard potential of the H ϩ /H 2 couple, seems attractive. Macrocyclic cobalt complexes are very competitive in that respect (3). In the past four years, we and others reported on cobaloximes-cobalt complexes containing bridged bidentate oximato ligands (see Scheme 1)-(4-7) as a new class of such catalysts with good catalytic stability and Ϸ250-300 mV overvoltage-the difference between the observed catalytic potential and the thermodynamic H 2 /2H ϩ ϩ 2 e Ϫ equilibrium. To date, these catalysts are among the most efficient ones and, thus, are currently exploited for the construction of H 2 -evolving photocatalytic devices that actuall...

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Photochemical hydrogen production catalyzed by polypyridyl ruthenium–cobaloxime heterobinuclear complexes with different bridges

Cited by 113 publications

References 38 publications

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

Supramolecular activation of a molecular photocatalyst

Cobalt and nickel diimine-dioxime complexes as molecular electrocatalysts for hydrogen evolution with low overvoltages

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