Ruthenium Formyl Complexes as the Branch Point in Two- and Multi-Electron Reductions of CO2

Toyohara, Kiyotsuna; Nagao, Hidemi; Mizukawa, Tetsunori; Tanaka, Koji

doi:10.1021/ic00126a003

Cited by 62 publications

(41 citation statements)

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“…insertions with a wide variety of unsaturated compounds such as CO 2 , [42][43][44][45][46][47][48] ketones and carbonylmetal compounds (Scheme 2). Reaction of 8 with an excess of CO 2 (450 mbar at -196°C) in [D 8 ]toluene indeed proceeded smoothly at room temeperature.…”

Section: Hydride Transfer Reactions Of Mo(h)(n)(depe) 2 (7) and Transmentioning

confidence: 99%

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

et al. 2006

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Starting from Mo(N 2 ) 2 (depe) 2 (1), the nitrido complex Mo(N)-(N 3 )(depe) 2 (2) was obtained by the reaction of 1 with Me 3 -SiN 3 . Subsequent reaction of 2 with HCl in CH 3 OH afforded the cationic imido chloride 3, which could be converted into the nitrido chloride 4 with sodium bis(trimethylsilyl)amide. From 3 and 4 the hydrido complexes of the type Mo(H)(L)-(depe) 2 [L = N (7), NBEt 3 (8)] were obtained by the reaction with the hydride reagents LiBH 4 and NaHBEt 3 . The hydridic character of the L n M-H bond of 8 was determined by DQCC measurements (bond ionicity i = 81 %). Hydride reactivity studies were carried out on 7 and 8; however, only 8 underwent hydride transfer reactions. 8 reacted with 4,4Ј-dichlorobenzophenone and acetophenone to afford the correspond-

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Section: Hydride Transfer Reactions Of Mo(h)(n)(depe) 2 (7) and Transmentioning

confidence: 99%

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

et al. 2006

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“…To produce highly efficient and selective electrocatalysts, the transitionmetal-based molecular materials are often considered [6][7][8]. The latter systems are capable of driving multi-electron transfers and, in principle, produce highly reduced species.…”

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confidence: 99%

Fabrication of Nanostructured Palladium Within Tridentate Schiff-Base-Ligand Coordination Architecture: Enhancement of Electrocatalytic Activity Toward CO2 Electroreduction

et al. 2014

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There has been growing interest in the electrochemical reduction of carbon dioxide (CO 2 ), a potent greenhouse gas and a contributor to global climate change, and its conversion into useful carbon-based fuels or chemicals [1][2][3][4][5]. Numerous homogeneous and heterogeneous catalytic systems have been proposed to induce the CO 2 reduction and, depending on the reaction conditions (applied potential, choice of buffer, its strength and pH, local CO 2 concentration, or the catalyst used) various products that include carbon monoxide, oxalate, formate, carboxylic acids, formaldehyde, acetone, or methanol, as well as such hydrocarbons as methane, ethane, and ethylene, are typically observed at different ratios. These reaction products are of potential importance to energy technology, food research, medical applications, and fabrication of plastic materials.Given the fact that the CO 2 molecule is very stable, its electroreduction processes are characterized by large overpotentials, and they are not energy efficient. To produce highly efficient and selective electrocatalysts, the transitionmetal-based molecular materials are often considered [6][7][8]. The latter systems are capable of driving multi-electron transfers and, in principle, produce highly reduced species. In reality, such multi-electron charge transfer catalysts tend to effectively induce the two-electron reduction of CO 2 to CO rather than yield highly reduced products in large amounts. Metallic copper electrodes are unique in this respect because they can drive multi-electron transfers. Mechanisms of the successful electrochemical reductions of CO 2 to methane and ethylene can be interpreted in terms of complex processes occurring at copper electrodes [9,10]. It is believed that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate [11]. Significant decrease of the reaction overpotentials can be achieved with the use of the metal complex modified electrodes capable of both mediating electron transfers and stabilizing the reduced products [12].Because reduction of CO 2 can effectively occur by hydrogenation [13], in the present work, we concentrate on such a model catalytic system as nanostructured metallic palladium capable of absorbing reactive hydrogen in addition to the ability to adsorb monoatomic hydrogen at the interface [14][15][16]. Under such conditions, the two-electron reduction of CO 2 typically to CO [12] is favored. When the reaction proceeds on palladium in aqueous KHCO 3 solutions, carbon monoxide together with hydrogen and small amounts of formate are produced [17][18][19]. Further, it has been postulated that CO and COOH adsorbates are expected to be formed at the surfaces of Pd electrodes at −1.0 V (vs. Ag/AgCl) and, subsequently, desorbed at even more negative potentials [20].To produce highly dispersed and stabilized palladium nanoparticles (as for Fig. 1a), we have generated them by electrodeposition (through consecutive potential cycling) from the thin film of...

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“…[4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate.…”

Section: -3mentioning

confidence: 99%

“…[1][2][3] During recent years, various catalysts, including noble and non-noble transition metals, as well as their numerous coordination compounds, have been considered as catalysts for CO 2 electroreduction. [4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate.…”

mentioning

confidence: 99%

Carbon Dioxide Electroreduction at Highly Porous Nitrogen and Sulfur Co-Doped Iron-Containing Heterogeneous Carbon Gel

Dembińska

Kiciński

Januszewska

et al. 2017

J. Electrochem. Soc.

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The functionalized carbon nanostructure, nitrogen and sulfur co-doped iron-containing highly porous carbon gel (obtained via carbonization of corresponding organic gel) is considered here as a non-precious metal catalyst for the electroreduction of carbon dioxide in neutral solution (potassium bicarbonate at pH = 6.8). Various electrochemical measurements (performed in distinct modes and under different conditions) have been utilized to comment about the catalyst performance and the reaction mechanism, in particular about the reaction products and the relative contribution from hydrogen evolution. At low overpotentials, the carbon dioxide reduction is favored over the hydrogen evolution reaction. Combination of conventional (stationary) stripping-type and hydrodynamic (rotating ring-disk electrode) voltammetric approaches has been demonstrated to function as an unique electroanalytical tool here. The CO 2 -reduction products can be identified as adsorbates (oxidative stripping voltammetry) or monitored continuously (electrooxidation) at the Pt ring electrode. Finally, the results of both electrochemical diagnostic and parallel gas chromatographic analytical measurements are consistent with the view that, in the examined range of the potentials, CO is the main CO 2 -reduction product. The electrochemical reduction of carbon dioxide (CO 2 ) permits, in principle, selective generation of carbon-based fuels (or syngas) and, indirectly, lowering population of one of green-house gases in the atmosphere. Due to existence of two strong C=O bonds in the CO 2 molecule, its electroreduction requires high overpotentials, and the low reaction efficiency still remains fundamental problem limiting practical applications. 1-3During recent years, various catalysts, including noble and non-noble transition metals, as well as their numerous coordination compounds, have been considered as catalysts for CO 2 electroreduction. [4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate. This step is often considered as the rate-determining one during the hydrocarbon formation.12 It should be noted here that, for example, copper is capable of successfully catalyzing electroreduction of CO 2 to multicarbon products, 13-15 palladium induces the reaction mainly to CO and H 2 and only small amounts of formate. 2,[16][17][18][19] Another important practical issue is related to the need of lowering costs of catalysts by substituting the noble metals with inexpensive abundant elements. There has been growing interest in catalysts based on nanostructured carbons that include the metal-free Ndoped systems and the metal-containing carbons. [20][21][22][23][24][25][26] For example, the biomimetic centers containing metallic moieties in the vi...

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Ruthenium Formyl Complexes as the Branch Point in Two- and Multi-Electron Reductions of CO2

Cited by 62 publications

References 0 publications

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

Fabrication of Nanostructured Palladium Within Tridentate Schiff-Base-Ligand Coordination Architecture: Enhancement of Electrocatalytic Activity Toward CO2 Electroreduction

Carbon Dioxide Electroreduction at Highly Porous Nitrogen and Sulfur Co-Doped Iron-Containing Heterogeneous Carbon Gel

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Ruthenium Formyl Complexes as the Branch Point in Two- and Multi-Electron Reductions of CO2

Cited by 62 publications

References 0 publications

Hydride Transfer Reactivity of Mo(L)(H)(depe)2 (L = N, NBEt3)

Hydride Transfer Reactivity of Mo(L)(H)(depe)2 (L = N, NBEt3)

Fabrication of Nanostructured Palladium Within Tridentate Schiff-Base-Ligand Coordination Architecture: Enhancement of Electrocatalytic Activity Toward CO2 Electroreduction

Carbon Dioxide Electroreduction at Highly Porous Nitrogen and Sulfur Co-Doped Iron-Containing Heterogeneous Carbon Gel

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Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)